How much energy comes from the Sun? On a hot day, it certainly seems
to be a lot, but few people know just how much energy is involved.|
Energy rates are commonly described in either Btu/sq. ft./hour (English system) or Watts/sq. meter. We will discuss a number of different descriptions regarding solar energy.
The first and simplest answer is for the amount of solar energy that has radiated from the Sun and is available in space at the Earth's distance from the Sun, before it gets into the Earth's atmosphere. That amount is 1,353 Watts/sq. meter or 429.7 Btu/sq. ft./hour, which is called the Solar Constant. That value has some slight variations: (1) the actual output of the Sun has very slight variations which seem to be related to the number of sunspots which exist at the time (about ±2%); (2) the distance of the Earth from the Sun varies during the year, being closest on January 3 (about ±3.3%); and (3) there are some slight periodic variations in the intensity of the short wavelength parts of the solar spectrum, possibly also caused by sunspot variations on the Sun's surface (around ±2%).
note 22 This is a US government NASA graph with a LOT of information in it! First, the (smooth dashed) curve that is called Black Body Radiation is the THEORETICAL wavelength distribution for an object which happens to be at the temperature of the surface of the Sun. Actually, the fact that we measure that curve is how we KNOW that the surface of the Sun is at 5762°K. Next is the Air Mass Zero curve which is the ACTUAL measured (by satellites) radiation at all wavelengths, above the atmosphere. By Calculus, the mathematical AREA under that curve totals the 1353 W/m2 that we we know arrives at the top of the atmosphere.
Next is an Air Mass One curve for a location where the Sun is exactly overhead (where the light has to pass through a distance of exactly ONE depth of atmosphere in the process). And finally the last and lowest curve also includes the effects of molecular absorption of different gases in the atmosphere. This results in a very irregular (lowest) graph. Again, using Calculus Integration, the total area under this graph represents the actual total energy which arrives at the Earth's surface (for a directly overhead Sun).
Since the Sun is not exactly overhead for most people, the sunlight actually has to pass through a longer (angled) path through the atmosphere. If that should result in TWICE the path length, we would refer to that as Air Mass Two, which clearly would be similar to the Air Mass One curve, but with more losses, that is, lower. There are ways to calculate the average angle that sunlight has to go through the atmosphere, and we find that the AVERAGE clear sky sun provides around 893 Watts/m2 (which is about 283.6 Btu/ft2/hr or very close to 100 Watts per square foot). Notice that this number is an AVERAGE value, and for a very high Sun, the numbers can be a little higher.
The graph shows an overview of the entire process, but many of the effects occur in specific stages.
The first specific major effect starts to occur when the sunlight gets to about 100 km (60 miles) above the ground. There is an abundance of ozone (a variation of the normal oxygen molecules that we all need to breathe) which begins at about that level. (Not actually an ABUNDANCE as it is always less than twelve parts per million of the atmosphere there!) Ozone tends be extremely effective at absorbing the shorter wavelengths of sunlight, the portion that is called ultraviolet. Careful examination of the Insolation graph above shows the portion of the spectrum where ozone is most effective in absorption. The rest of the sunlight is nearly unaffected, so the visible light and the infrared are transmitted downward. This has two major effects: (1) by the ozone absorbing the ultraviolet, it gains heat and so that part of the atmosphere gets warmer. This acts to heat a layer of our atmosphere called the Stratosphere from the top down. There are probably convective circulation cells in the stratosphere, but little research seems to have yet been done to study it, and it is still unclear if that action has any effect on weather or anything else; and (2) since most of the ultraviolet energy is absorbed by the ozone layer, very little remains that gets transmitted down to the surface where we are. There is still enough to cause us to get a severe sunburn, but we are protected from the probable fatal effects of getting all the ultraviolet radiation that was present in the Early Earth solar radiation. This last is why many scientists are extremely concerned that human activity seems to be damaging the ozone layer. Some chemicals such as ones called CFCs (chloro-fluoro-carbons) such as Freon seem to rise up in the stratosphere and react with the ozone to break it down. Such chemicals provide free-radicals of chlorine, which can react in the following way: Cl- + O3 = OCl + O2 and then OCl + O3 = Cl- + (2)O2. A single chlorine free radical can therefore cause two ozone molecules to break down into three normal oxygen molecules and then even wind up ready to do it again.
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As the sunlight proceeds downward toward the earth, it passes an altitude called the tropopause. Nothing special occurs there but it is the altitude that separates the stratosphere (above it, and heated from above by the ozone heating) and the troposphere (below it, and heated from below by the various effects described in the following text). It is therefore the coldest portion of the Earth's atmosphere (except for a region extremely high, almost where satellites orbit). Around the ozone layer (32 miles or 160,000 feet or 50 km up), the atmosphere is around 20°F or -5°C, fairly warm. At the tropopause (8 miles or 40,000 feet or 13 km up), it is far colder, around -70°F or -55°C. That is roughly the altitude that jet airliners fly at. Below that altitude, the atmosphere becomes much warmer, getting up to an average of around 59°F or 15°C at sea level.
Once the sunlight has passed the tropopause, it gets into the troposphere, the layer of the atmosphere that we live in and which all weather occurs in. Most specifically, there is carbon dioxide and water vapor in the troposphere, both of which absorb a lot of the infrared part of the sunlight. This absorbed energy heats up the air and causes convection (circulation) to occur in the atmosphere, which causes all the Fronts and other air circulations you see in the daily weather forecasts. It is a primary energy source for most weather phenomena.
When scientists suggest that more severe weather might occur (such as stronger hurricanes and tornadoes and thunderstorms) it is because of this. If more carbon dioxide is present in the atmosphere (and it definitely is), then SOME more solar heat is absorbed (from INCOMING sunlight) into the atmosphere by that carbon dioxide, and there is therefore SOME more energy present to drive convections and the other motions of the atmosphere. It turns out that both carbon dioxide and water vapor have an even far GREATER effect regarding radiation that the Earth tries to send off to deep space! The Earth is much cooler than the surface of the Sun, so the Black Body radiation it gives off is very far in the infrared wavelengths, while sunlight from the very hot Sun's surface has large amounts of both visible light and ultraviolet light in it. Why is this important? Because both carbon dioxide and water vapor are tremendously effective at absorbing INFRARED energy, while letting most visible and ultraviolet energy to pass through.
The result of this is that the energy from sunlight can get TO the Earth pretty easily, but then the energy that the Earth tries to radiate off to deep space tends to get absorbed in the atmosphere by those two gases. Since the gases absorb that energy, they get hotter and they then re-radiate infrared energy. About half of that re-radiated energy goes upward and outward, finally making it to deep space. The other half gets re-radiated DOWNWARD, back toward the Earth.
This therefore provides an ADDITIONAL energy (heat) source for the Earth. It is not actually additional energy, but energy that gets used a second (and more) time to heat the Earth. The result is then that the Earth will warm up, what is referred to as Global Warming.
Much of the detail of such things is still unknown, but the basics are definitely known. With the Earth and atmosphere becoming warmer, there is more available energy in the gases, which seem certain to enable stronger storms. That added energy to the atmosphere has to somehow get "used up", and two common ways that happens is getting converted to kinetic energy (air motion) by convection and getting converted to electrical (lightning) energy as related to cloud formation.
The water vapor in the atmosphere starts out low in the atmosphere where it is warm, which is why it evaporated from liquid surface water in the first place. If it rises in the atmosphere (due to convective circulation as mentioned above), it gets to cooler levels. If the tiniest specks of dust are present, the water vapor can condense out onto those dust specks to form very tiny droplets of water. The droplets are so tiny that they do not fall, because the convective upflow of the air easily supports them. This is how a cloud forms. It is no longer water vapor but actual water droplets, just really small ones! Clouds are important in our discussion here because they are very reflective of visible and infrared sunlight. This reflected light therefore never gets down to us on the surface, and it also does not heat the clouds or air, but simply bounces back out toward outer space.
The amount of carbon dioxide in the atmosphere, the amount of water vapor and the quantity of clouds are each quite variable, but they tend to average out over long periods of time, and so these various effects of absorption and reflection can have minimal effect (for example, on a cloudless summer day in a desert) up to an extreme effect (for example, an extremely overcast day with thick clouds). These effects are the primary ones that drive the Earth's weather, and since they are each so variable, it makes weather forecasting the difficult job that it is. Even the best weather forecaster can be wrong when unexpected changes occur locally in any of the above, or in any of their consequences (specifically, the convection cells and the winds).
Summary so far: If we consider the Solar Constant (1,353 watts/square meter) to be 100% of the incoming solar energy in space approaching Earth, about 34% of that energy gets reflected off clouds and dust particles and the Earth. That leaves around 893.0 w/m2 or 283.6 Btu/f2/hr to actually get TO the Earth. This is for an AVERAGE location, so when the Sun is high overhead and there are no clouds, the instantaneous amount can be a little higher than this, as high as about 340 Btu/ft2/hr, or 1,070 Watts/sq. meter. On the clearest possible day, this is about the best solar energy input that is possible. However, on the average, the 283.6 Btu/ft2/hr is more realistic.
Remember that this is a reasonable maximum, when the sun is high in the sky. Geometrical analysis shows us that we could divide this by four to get a 24-hour Average value (meaning counting all 24 hours of the day. Therefore some reference sources use a value of 71 Btu/ft2/hr or 223.0 w/m2 as an average value. That value can sometimes be useful in that we could then estimate that FOR A FULL DAY, we might say that we have access to 71 * 24 or about 1700 Btus per whole sunny day per square foot of collector area. (5300 Watt-hours per meter2 per whole sunny day.)
On an average, for cities like Chicago, where average sky clearness is only described as around 35%, the realistic daily total available is considerably less than this. Therefore, for practical application, it makes sense to think of safely expecting only around 2000 watts per meter2 per average winter day or 560 Btus per full average day per square foot of collector area. This is true whether the application is for making electricity (PV) or in heating water or air for a residential application.
We might then say that an absolute maximum of about 1070 w/m2 is available briefly near noon on a perfect day, but that 5300 watt-hours is fairly likely for the entire day. We sometimes estimate that a fully sunny day (many hours) is therefore about equal to about five hours of noon sunlight, that is (5300 = 5 * 1070).
Regarding solar heating equipment, this is when the many heat losses of the equipment itself are now considered. For PhotoVoltaic panels, the efficiency of many available PV panels is around 7% regarding converting the sunlight to electricity, so we might say that an entire day of bright sunlight might create 5300 watt-hours/ square meter of panels * 0.07 or about 370 total watt-hours for a one-square meter array for an entire sunny day.
Peak Power Rating vs. Average Power Rating|
You may drive a car which was advertised as having a 495 horsepower engine, and that may have even affected whether you bought that specific car. That engine rating can be called a PEAK POWER RATING, being the greatest amount of power that it is capable of producing. When creating that enormous amount of power, it is realistic to expect to get around one or two MPG gas mileage. But for AVERAGE driving on an Interstate Highway, your engine only produces around 40 horsepower, during which you may get 25 miles per gallon gas mileage. This AVERAGE situation is a far more accurate description of what YOU CAN ACTUALLY EXPECT, such as regarding gas mileage. Both situations are true, but they are extremely different. One is a situation which sounds very impressive, but which you will likely NEVER actually experience, except possibly rarely for a second or two at a stoplight! The other is a situation which you may experience every day of driving! IF you were only given ONE of the numbers, which would you consider more important to know?
Whenever electricity ratings are given for alternative energy devices, they seem to always be PEAK POWER RATINGS, meaning the greatest amount of electricity or power which can be created. That is entirely different than ratings for AVERAGE USAGE CONDITIONS, which would be realistic numbers of amounts of electricity or power which might NORMALLY be expected to be provided. The discussion and calculations included here will indicate that OFTEN the realistically expectable amounts of electricity or power is only around ONE-TENTH that of the PEAK POWER RATINGS. But no one bothers to mention this important fact! So advertising makes claims of spectacular performance numbers for photovoltaic solar-electric panels, and for solar roof panels, and for electric vehicles, and for Hybrid vehicles, and for windmill-electricity-generation, and even for FUTURE giant windmills and hydrogen as a fuel. They invariably state PEAK POWER RATINGS, like that 495 horsepower engine in the car, numbers that may be technically true but are extremely misleading.
(The 7% figure for PVs is for the most economical technology of solar cells, which is based on Cadmium Sulfide (CdS). There ARE higher efficient technologies which exist, such as those based on Gallium Arsinide(GaAs), but they are far more expensive and not within the price range of most people. There are even more expensive technologies that are based on silicon semiconductor technologies, which require a [metal] silicon ingot to be sliced so thin that sunlight can pass THROUGH it, which is extremely expensive to do! So higher efficiencies exist in solar cells, which are reported in media stories, but they are currently far too expensive for broad use. This all results in MOST commonly available solar cells being cadmium sulfide, and therefore around 7% efficient.)
That's about the total area of the top of a picnic table, which often involves several thousand dollars worth of PV panels. Note that this expense is to be able to get a MAXIMUM electric production of around 0.37 kWh of electricity from a full sunny day. If electricity costs around 10 cents per kWh from the power company, this is under four cents worth of electricity being produced per hour on each sunny day! Over a period of a month, around one dollar's worth of electricity might be provided. Since the equipment is extremely expensive, at a payback of one dollar per month, it can never come close to paying for itself, much less actually saving the owner any money.
PV panels need to become FAR less expensive and having far higher efficiency before they become practical alternatives regarding supplying electricity.
For solar water heating panels: The (glass) cover plate(s) each reflect a few percent of incoming energy and also absorb a small amount; insulation around the (hot) collector loses captured heat; piping or ducts have heat losses; any method of heat storage also loses heat through insulation; and every stage of heat transfer must be "driven" by temperature differentials to get the heat where it is desired. These various issues are why effective solar energy applications require extensive Engineering design. Almost any "solar product" seems to work great on a hot sunny day around noon! But for any application to provide reliable performance, all the different aspects of a system must be maximized. Unfortunately, very few building contractors seem to yet fully understand all the necessary subject areas, and so effective solar heating and other quality solar products are still sadly rare. It may be another 20 years before the products and installers advance to the point of most solar products being worth buying.
When a large volcano blows up, for example, such as Mount Saint Helens, or Mount Pinatubu, or Krakatoa, millions of tons of find dust particles are shot up into the air. Many are so tiny that they remain suspended in the air for years! They can circle the Earth many times during that time. The dust itself can block sunlight from getting to the surface, while also absorbing extra energy in the atmosphere, and the dust can also provide countless particles for water vapor to condense upon to form more clouds. In both cases, severe changes in the Earth's weather patterns can result. The year 1816 is sometimes called the year without a summer, since it never really got warm and snow fell in most of the United States even in July and August, and that was due to a volcanic explosion a few months earlier thousands of miles away. It is thought that a similar volcanic explosion occurred around 600 AD which might have caused several years of unusual cold for Europe, where crops all failed and starvation was a severe problem.
In this general regard, our modern industrialized society is probably doing some similar effects. All homes are heated with fossil fuels (oil or natural gas or by electricity, which is indirectly usually coal) or with wood or propane gas, all of which creates large amounts of carbon dioxide gas as the primary chimney product. All vehicles (cars, boats, aircraft) use gasoline, diesel oil, kerosene, or jet fuel, which similarly produce carbon dioxide gas as the final waste product of burning. Nearly all industrial processes create even more carbon dioxide gas. The amounts are rather amazing, mostly because the carbon dioxide gas is the primary result of all those chemical reactions combining carbon from any of those fuels with oxygen from the atmosphere.
In fact, you can check in any annual Almanac to confirm that we humans are adding 15 to 30 billion tons of carbon dioxide to the atmosphere every year now! That is roughly 400,000,000,000,000 cubic feet of carbon dioxide that we add to the atmosphere EVERY YEAR! (NOTE, Feb. 2007: Richard Branson and Al Gore announced an Earth Challenge Prize of $25 million to anyone who can figure out how to REMOVE carbon dioxide from the atmosphere! (Branson included some trickery in that offer, because even a small part of that prize would not be paid until after 2011 and then nearly all of that highly publicized Prize would not be given until the process actually proved effectiveness for the next ten consecutive years! This is from the actual Application Form for applying for that Prize, where it also claims absolute and complete ownership of any technology submitted by Branson and his Virgin company. VERY tricky stuff! I am VERY disappointed with Branson for doing such things!) They must not actually realize the scale of the problem! Even to remove the carbon dioxide we add in a single year, that would involve removing nearly a million times as much carbon dioxide gas as has EVER been removed by all machinery in all history! In a Press Conference, Branson enthusiastically mentioned concepts such as extracting the carbon dioxide from the atmosphere and pumping it down into the ground! That concept is now so politically popular that it already has its own name, Sequestering. He must not realize that it would percolate back up through the ground within months and be back in the atmosphere! He also clearly is unaware that even if he got some method to work, it would necessarily involve at least FOUR MILLION FULL TRUCKLOADS EVERY DAY, or one and a half billion full truckloads each year! I would think that SOMEONE would have remembered all the terror caused when they were told that Radon gas was constantly seeping up through the ground. And Branson and others think that carbon dioxide pumped in under far higher pressure would NOT? Duh??? (The gesture was potentially admirable for its apparent intent, but extremely unrealistic regarding it actually accomplishing the desired task.)
We reliably also know that the TOTAL carbon dioxide in the whole atmosphere is around 3000 billion tons. (Anyone can simply calculate the total mass of air in the atmosphere by multiplying the 14.7 pounds per square inch atmospheric pressure (which is actually simply the total weight of all the air directly above that square inch) by the total surface area of the Earth, to get 5.136 * 1018 kg or 1.133 * 1019 pounds or 5.67 * 1015 tons. We know that the carbon dioxide component of that is roughly 390 parts per million (by volume). A simple density adjustment (of 1.529) gives a total of around 3.0 * 1012 tons total, the number given above.)
So every year now we are adding (as much as 30 billion tons) about one additional per cent of carbon dioxide to the atmosphere! Since it is invisible, we are not very aware of it, but an average car causes several tons of carbon dioxide gas to go up into the atmosphere every year! (It is very easy to calculate) If there were only a few cars, there would be no serious problem, but since there are hundreds of millions of cars in use, the total amount of carbon dioxide gas being added into the atmosphere is astounding!
Once the Earth absorbs that energy, it warms up. In fact, the Earth necessarily warms up to a point where it would then be radiating heat outward in a total amount equal to the energy coming in from the Sun, which is a situation called Equilibrium. The Earth would then be at a specific temperature where it could exactly radiate the same amount of heat, meaning that the Earth's surface would then stay at the same temperature, not heating or cooling except briefly.
Before the Earth had any atmosphere, there were only those two effects, which are easy to calculate. It is easily shown that the average temperature of the Earth's surface then had to be around -23°C or -9°F.
However, once the Earth developed an atmosphere, and that atmosphere contained carbon dioxide and water vapor, the heat radiated away from the Earth had more trouble getting away! The carbon dioxide and water vapor in the atmosphere tended to ABSORB the infrared heat that the Earth was trying to radiate away.
The atmosphere can therefore become far warmer, just because of a "blanket effect" of a surprisingly small quantity of Carbon Dioxide in the atmosphere. We are about to show that we NEED a certain amount of carbon dioxide in the atmosphere!
It is actually easy to calculate the average temperature the Earth's surface SHOULD have, at our distance from the Sun. We know that there must be an average balance between the energy coming in from the Sun (and a far smaller amount that comes up from inside the Earth from radioactive decay going on down there) and the energy being radiated out into space. This is known as Equilibrium. Again, for short times (months or years) and in specific places (equator or poles) there may not be an equilibrium, but that there must be on a longer time scale and for the whole Earth.
We know the amount of solar radiation coming in. Above we gave the value of the Solar Constant. That tells how much energy from the Sun gets to the top of the Earth's atmosphere for each square foot or square meter of area. If we just multiply by the total area of the Earth presents to the Sun (NOT the SURFACE area!), we can know the total amount of energy that is aimed at the Earth. Once we subtract off the amount that gets reflected back out into space, we learned above how much actually gets absorbed into the Earth and its atmosphere. Whatever total amount that is, and we can fairly easily calculate it, it must be the same as the amount of radiation the Earth gives off to space, for that Equilibrium.
There is a well-proven Stefan-Boltzmann law and equation that calculates the amount of outgoing radiation that any body must give off at any specific temperature. We will not go into those details here, but the radiation varies as the FOURTH POWER of the absolute temperature of the surface! Fairly small changes in the average surface temperature of the Earth therefore can really change the amount of radiation we give off to space.
Actually, analysis of air bubbles in ice cores has shown that the carbon dioxide in the atmosphere has fluctuated over time, but apparently within a relatively small range. The Vostok ice-core data (Barnola, Raynaud, Lorius; 2003) gives values for the past 419,000 years which are never above 300 ppm and never below 182 ppm. For the 800 years between 1000 AD and 1800 AD, it stayed very close to 280 ppm, never being more than around 5 ppm away from that.
In 1958, our government started precisely measuring the concentration of many gases, including carbon dioxide, at Mauna Loa mountain in Hawaii, monthly. The annual average for 1959 was 315.83 ppm. By 1989, just forty years later, it was already 352.75 ppm. Similar measurements are made at the South Pole.
In just the past 100 years or so, we have increased that proportion of carbon dioxide in the atmosphere from that fairly constant 280 ppm to about 390 ppm. If the relationship is linear, which seems fairly likely, (and many researchers consider to be true) and if carbon dioxide is the principle cause, which also seems very likely, this indicates that the PRESENT stable temperature for the Earth should be (390/280) * 450°R (the initial Equ or 92°F warmer than the initial -9°F. [if 280 ppm caused the 66 degree increase, then proportionally, 390 ppm would cause a 92 degree increase, to a current 83°F.]
Not even counting the additional carbon dioxide we will pump into the atmosphere in coming decades, we have ALREADY caused a twenty-five degree F rise in the atmosphere (which may take many decades to actually appear because of how massive the atmosphere and Earth is). But there can be no doubt from this reasoning that we have ALREADY caused a coming 25°F rise in the average temperature of the Earth's atmosphere and surface. So when alleged "experts" claim that there will only be a two-degree rise over the next hundred years, they clearly have no idea what they are talking about!
We can even use published data to confirm this! Any annual Almanac can confirm that the world now sends 15 to 20 billion tons of new carbon dioxide into the atmosphere each year, nearly all of which comes from vehicle exhausts and electric power plants. We know that there are around 3,000 billion metric tons of carbon dioxide in the atmosphere already (using the Mauna Loa data figure from 1987). [We know the total mass of the atmosphere and we know the fraction of it that is carbon dioxide.] Since the 3,000 billion tons of total carbon dioxide is the 390 ppm, then the 15 to 20 billion tons that we add each year must logically be increasing that fraction by about 2.0 ppm every year [simple proportion]. This actually is seen in the data. From 1979 (336.68 ppm) to 1989 (352.75 ppm) there was an increase of 16.07 ppm in ten years, or an average of 1.6 ppm each year.
We have shown that a 2.0 ppm increase is clearly directly due to the carbon dioxide that humans have added to the atmosphere. The small remainder may be due to the massive removal of rain forests, which have eliminated countless trees from being able to remove carbon dioxide from the atmosphere.
And now that China is going industrial, on an enormous basis, this contribution will get far faster and worse.
We can project this ahead, with reasonable assumptions of China's contributions, where the annual increase such that the annual increase rises to around 2.2 ppm or even 3 ppm.
This is catastrophic beyond imagination! Few trees will be able to survive and actually live and expel oxygen at 35°F hotter than they are used to. They can't go anywhere, so they are nearly all likely to simply die. This would mean that THE major source of oxygen in the atmosphere no longer existed. Food supplies, too, would be essentially gone. As animals and humans lived and breathed and used it up, far less new oxygen would be formed. This might easily represent a death sentence for all animal and human life on Earth, except for very small numbers of individuals who were somehow able to survive on minimal oxygen. We know that there are about 1.2 * 1018 kg of oxygen in the atmosphere. We know that photosynthesis of the world's plants adds around 2.6 * 1014 kg of oxygen to the atmosphere every year, and we know that the vegetative decay of dead trees and plants and animal wastes and carcasses and respiration uses up roughly that same total every year.
In the event that all plants and trees died, humans and animals would then only have the existing oxygen in the atmosphere on which to live. While there were still plants to rot and decay, that 2.6 * 1014 kg/year of oxygen would get used up (and never be replaced), of the existing supply of the 1.2 * 1018 kg. This implies that there is enough oxygen in the atmosphere for humans and animals to breathe for around 4,600 more years. Actually, more, because once there were no more plants to decay, the consumption of oxygen from the atmosphere would be greatly reduced.
So, the concern about running out of oxygen is not one we truly need to see as urgent, although once the oxygen is gone, that would certainly be it for humans and animals on Earth!
However, of all or most plants died, the ENTIRE source of food for all animals and plants would end. A very small number of humans might be able to survive for a while, by possibly manufacturing food nutrients from fossil fuel, but such a situation, total lack of vegetable and animal food, would be incredibly grim, and THAT would occur within a matter of months of plants all dying.
It turns out that this concept is not even new! (Archer and Barber, 2003, Photosynthesis and Photoconversion, Chap 1, p.4, calculated that several years ago, and expressed the concern that the end of human and animal life may soon happen.) They also noted and calculated that if all plants were gone and people were still breathing oxygen, we would consume all the remaining oxygen in the atmosphere surprisingly quickly! (But we would run out of food far quicker.) They calculated the oxygen consumption to take around 4,600 years. Few food crops will be able to survive that great temperature increase either. That suggests that, very quickly, in months, that the entire food supply for humans and animals might end (ibid).
By the way, the fact that this matches so extremely well seems to imply that the scientists who first calculated the 36°F Equilibrium temperature must clearly have KNOWN all this stuff some years ago! Why didn't they speak up more loudly about the catastrophe that we are headed for?
Much of our possible survival may depend on whether plankton in the oceans can survive such great temperature increases. Plankton is actually the greatest source of oxygen in our atmosphere, with trees and land plants being second. (They are tiny, but there are a LOT of them!) If they can, humanity and animals have a chance. If not, there is no chance at all.
If we really allow the Earth to heat up by 35°F, where nearly all trees and grasses can no longer live, and if plankton also die from that excessive heat (as has been seen in some coral reefs), then there will be two separate new problems. One is that there would no longer be any plant food supply for any animals or humans to eat. That problem would be very urgent, in a matter of months. The other is that there would no longer be any significant way that carbon dioxide could be removed from the atmosphere and oxygen sent into it. Without any source of oxygen, animals and humans could not survive. As noted above, that would likely not be a severe problem for a few thousand years. However, the other half of that, the removal of carbon dioxide from the atmosphere is also a very serious issue.
When occasionally people refer to a "runaway Greenhouse Effect" it is this, where more and more carbon dioxide will accumulate in the atmosphere, without any way for it to be removed (due to the plants being gone), and the global warming would become faster and faster. Currently, plants remove around 300 * 1012 kg of carbon dioxide from the atmosphere every year. If photosynthesis suddenly stopped, that would end and all that carbon dioxide would remain in the atmosphere. There are currently around 2500 * 1012 kg of organic carbon in the biosphere, which would all rot and decay over a period of decades, and release about 7000 * 1012 kg of additional carbon dioxide into the atmosphere. That would essentially quadruple the current amount of carbon dioxide in the atmosphere, which would cause enormous temperature increases due to the effectiveness of that blanketing effect.
It is REALLY important to understand that we have ALREADY fouled things up enough to cause the 25°F rise. It is unavoidable because IT HAS ALREADY HAPPENED. Even if every driver on Earth scrapped all his vehicles today, and all coal-fired electrical generation plants completely shut down today, and we stopped ALL heating of all houses, apartments, stores, factories and schools today, we are STILL going to have that 25°F rise of the average temperature of the entire Earth.
Every additional day of using ANY of those things will just make the situation even more grim. So, when politicians announce that they intend to reduce greenhouse emissions by 20% by the year 2050, it is meaningless. The cows have already run away so there is no reason to talk about some minimal thought of closing the gate 43 years from now.
No politician, and no country, will ever actually DO anything serious about this. As long as they think that "the other guy" won't, they would never agree to absorb the many very grim hardships that are obviously and certainly necessary. Given that there is a valid possibility (mentioned above) that we may have already done enough harm that all sources of oxygen (trees and maybe plankton) will likely die within a hundred years or so, there will simply be denial. We all saw in the movie Titanic that the band kept playing until the very bitter end. We are now all on board, and there seems little doubt that politicians and all other leaders will NOT do anything to adversely affect their countries' businesses' profits or their residents' comfortable lifestyles, until the day when the band can no longer play.
A FEW people probably ARE willing to completely give up driving a car. But not nearly enough to actually make any difference.
We have already "hit the iceberg" but it is an absolute certainty that we will choose to stay in denial, and effectively even be looking for more icebergs to hit! Human nature is something special!
It does not even take a really good scientist to see that this is an obvious result. It is generally referred to as "Sea Level Rise due to Global Warming". More carbon dioxide gas in the atmosphere must certainly result in additional heating of the atmosphere, due to the absorbed energy. There are many apparent consequences of global warming, but one of the most obvious and most problematical is that the Polar ice caps figure to partially or completely melt. (Early in 2008, a group of expert Researchers announced that the ENTIRE North Polar Ice Cap will MELT by late September of 2013!) This results in those billions of gallons of frozen water (ice) (much now being up on top of land) then being added to the waters of the oceans, which causes the height of the water in the oceans to rise. Many major cities are built on coastlines, and they will be flooded and destroyed if ocean levels rise even 100 feet. New Orleans is already 7 feet BELOW the ocean level, and must already have a protective dike completely surrounding it. New York, Tokyo, Rio and most every other major world city was started where some major river joins the ocean, so they are all in great danger of rising sea levels.
The comment above, regarding sea levels rising, has inspired some amazingly nasty e-mail to be sent to me! In general, such writers feel that it is POSSIBLE that sea levels might rise 2" or so, over the coming hundred years, but they tell me that I am an idiot for saying even "feet" and four letter words often accompany their comments regarding "even 100 feet." I never mind receiving criticism, as long as the writer has actually studied to understand the subject of his or her complaint! In this case, that is certainly not true, and such writers are simply repeating things they have heard other ignorant people claim before. I note that there have been several recent 2005 and 2006 PBS programs that describe how the ice cap on Greenland is melting back (and falling into the ocean) at 150 FEET EVERY DAY! Each year, TEN MILES of ice near the edges of Greenland is melting! This is a LOT of ice! In a hundred years, that is a THOUSAND MILES of Greenland that will be without ice, most of the entire ice cap that is now on Greenland. However, Antarctica represents a far bigger disaster in the works. Antarctica is around 5,400,000 square miles (14,245,000 km2) in area. Sonar soundings indicate that the ice on Antarctica averages around 1.5 miles (2000 meters) thick. That means there is around 8,100,000 cubic miles (28,500,000 km3) of ice now sitting on Antarctica. (nearly all of it currently above sea level). Actually, there may be more than that! It is known that the weight of all that ice has depressed the Crust of the Earth there by around 560 meters (1900 feet) and so as the ice melts and the weight is removed, the Crust will rise back up. That may then add additional ice to the problem, ice which is currently below sea level but then would be above! So the total of volume of ice which might be added to the ocean volume might be around 36,500,000 km3 instead.
That is 28.5 million (or possibly 36.5 million) cubic kilometers of ice that would melt to become essentially the same quantity of water that would get added to the oceans. Any good resource can confirm that there are around 361.3 million square kilometers of ocean surface on Earth. Simple division says that if/when all that ice on Antarctica melts, the sea levels will all rise by 28.5/361.3 kilometer or 78.9 meters or around 260 vertical feet! (or more, 36.5/361.3 kilometer or 101 meters or around 330 vertical feet!) How hard is that to calculate? In any case, a ten-foot rise which would destroy many huge world cities would hardly be a start at Antarctica melting! There can be no doubt that enough Antarctic ice will melt during THIS century where most major world cities will no longer be able to exist. THIS is a problem! But NO ONE seems willing to even think about this coming situation!
The PBS programs also note that roughly 1/3 of the North Polar Cap is already GONE, melted! (2006) Where has all that ice/water gone? It IS true that much of the North Polar Cap ice which has already melted had been FLOATING in the Arctic Ocean, so that when it melted, it did not ADD TO the total volume of the oceans. In fact, as water, the volume is actually slightly LESS than it was as ice, but the DISPLACEMENT of ocean water would not change. So, until the ice on Greenland and Siberia and Canada and Alaska and all the other glaciers (which are ABOVE sea level now) melt, the water level will not materially rise due to that cause.
There are other published government figures that give a different but similar rise. That data defines the current locations of the various amounts of water on Earth: 97.1% in the oceans; 2.24% in the polar ice caps and glaciers; 0.61% in groundwater; 0.016% in lakes; 0.001% in the atmosphere; and 0.0001% in rivers. Using these figures, if the glaciers and ice caps all completely melted, then the amount of water in the oceans would increase by a factor of (97.1 + 2.24) / (97.1) or 1.02307. The current average depth of the oceans is around 12,500 feet, so with those glaciers and ice caps melted, sea levels would necessarily rise to 12,788 feet, meaning that all sea levels would rise by 288 feet. This is essentially an accurate confirmation of the Antarctica 260 foot-rise-effect figure given above.
It seems astounding that there are alleged "experts" who announce in Feb 2007 to TV reporters that "sea levels may rise by 1 millimeter per year." (that is one inch in 25 years!) Where did such people get their education? Who is paying them? (which is probably a more important question to ask!)
There is actually a fairly large part of the ice sheet of Antarctica which is showing signs of completely breaking loose, which means that it would then soon melt as large icebergs. There is a section that broke loose a couple years ago that was the size of the whole State of Connecticut! Why doesn't anyone seem to realize the simple calculations like above, which any school kid should be able to do? If a chunk of Antarctica ice that is only 1/300 the size of the whole continent would slide off and then melt, or otherwise just melt and flow off the continent, how could anyone say that would not result in approximately ONE FOOT rise in all the oceans' sea level, nearly immediately? Where do they think that ice/water would go? A SINGLE EVENT, and not even an especially huge one, could rapidly place enough additional water into the oceans to raise sea level by a foot! Yet there are "experts" who announce (in early 2007) to the public that the sea level rise will only be one millimeter (1/25 inch) per year? Isn't this some sort of bizarre shell game being played on us? Just so that giant corporations can continue to make spectacular profits? Arrrrrgggggghhhhhh!
The worst part of this situation is that the effects of additional carbon dioxide gas in the atmosphere appear to be delayed. We collectively are pumping astounding amounts of carbon dioxide gas into the atmosphere every day. But the atmosphere is huge, and even those additions only make slow changes. There is an additional effect, that the atmosphere cannot really significantly change temperature without the Earth also changing temperature by the same amount. It happens that the rock that makes up most of the Earth's Crust conducts heat very slowly, and reliable calculations suggest that it may take around 140 years for the Earth's Crust to get to a new Equilibrium temperature.
Once carbon dioxide gas is in the atmosphere, it pretty much stays there, with only one normal method of being used up, by the activity of plants, which take in carbon dioxide gas and give off oxygen as a result of photosynthesis. A few insightful scientists have noted that we STILL have carbon dioxide in the atmosphere from the very first Model T cars of a hundred years ago! The point being, the net amount of this invisible carbon dioxide gas is continually rising in the atmosphere. note 2
Even that effect that initially seems attractive, of the plants REMOVING carbon dioxide from the atmosphere, is not nearly as wonderful as it first seems. Yes, living plants do that, and remove 300 billion tons of carbon dioxide from the atmosphere each year. But when those plants die, or when the animals that ate them die, everything then decomposes, which has the direct effect of again releasing all that carbon dioxide back into the atmosphere. We might be able to remove a lot of carbon dioxide from the atmosphere for a few months, but when the plants and animals die, it is all back again.
Some evidence of polar ice cap melting is certainly already being seen, but it may be another 20 years before the melting is at a truly rapid rate. NOTE: in early 2008, a group of respected Arctic researchers announced that the ENTIRE North Polar Cap will likely have completely melted by September 2013, just a few years from now! At that point, if political leaders finally decide to act to control global warming, there will still already be enormous amounts of additional carbon dioxide gas in the atmosphere for many years, and even decades or centuries, afterward. But no one seems to comprehend the AMOUNT of carbon dioxide involved! We are adding around 144,000,000,000,000 cubic feet of carbon dioxide to the atmosphere every years, just primarily from vehicles and from electric power plants. So even if all sources of carbon dioxide gas were stopped at that time (which no businesspeople would agree to anyway), all the bad effects of global warming would continue for many, many, many years, and those many cities would and WILL certainly be flooded and lost. Most of the very worst effects will likely occur after we are dead, but our children and grandchildren face a future that is dire indeed.
In other words, the damage that we have already done, of causing the equilibrium temperature of the earth to rise from the current 59°F to what should already apparently be 83°F, cannot even be slowed or reversed! Around 140 years from now, it appears that is the unavoidable reality.
Regarding sea levels rising, there is actually also another effect, regarding the density of water at different temperatures. As water warms up, it becomes slightly less dense, meaning it takes up more volume. So even without any ice melting at the North and South Poles, there would be a noticeable (and also easily calculable) sea level rise simply due to that density change of the water. We know that the average depth of the world's oceans is around 12,500 feet. At 58°F (20°C) the specific gravity (essentially density) of water is 0.99823. At 22°C (or 61.6°F), it is 0.99780. (like most other things, it expands when it is heated, so the density drops.) The proportion of these two numbers is 0.99823/0.99780 or 1.00043. So the average depth of the ocean would increase by this proportion JUST BY THE DENSITY DIFFERENCE (not counting any added ice). Therefore, the 12,500 average depth would become 12,505.4 feet, That means that once the average ocean temperature rises just TWO DEGREES CELSIUS, the oceans WILL increase in depth by around 5.4 feet, raising the oceans sea level by that 5.4 feet! If we do this calculation for the 83°F (or 34°C) that we calculated as the present correct Equilibrium temperature for the Earth, this becomes more significant. The specific gravity at that temperature is 0.99440, so we have a multiplier of 1.00385, which gives the average depth of the oceans then to be 12,548 feet. So, even without any ice melting, we have a situation where the sea levels will certainly rise by around 48 feet.
Even if NO ice melted, and the oceans simply warmed up by just 2°C, the resulting sea level rise of 5.4 feet will be catastrophic world wide. Venice, Italy and New Orleans, Louisiana will be entirely underwater and gone forever. A good portion of the State of Florida will be underwater, as will much of the countries of Bangladesh and Indonesia and many others. Nearly all major cities developed based on being ocean ports, and all their pier areas will be completely underwater, even if only 5.4 feet sea level rise occurs! But the rise will be FAR higher than that, because ICE WILL MELT!
Now, no business and no nation is going to seriously consider cutting back on any activities that now produce all that carbon dioxide gas! "Tell the other guy to cut back, I do not see that I am doing any harm, and I only make a small amount anyway! And it would hurt my business!" If anyone did cut back, by restricting or eliminating home heating, or driving, or almost any industrial process, then it would be seen as a tremendous financial disadvantage for that company or nation, because all their short-term profitability is absolutely dependent on processes that all create carbon dioxide gas in the atmosphere! So, the reality is that NO ONE is going to make the slightest real move toward even limiting the emission of carbon dioxide gas into the atmosphere, until a worldwide crisis is considered absolutely urgent. And, by then, it will be far too late to actually do much. (It is pretty certain that it is ALREADY far too late to save us.) Any actions taken then will really only (potentially) benefit the great-grandchildren of people then living, mostly related to whether they even have any chance of survival. It is hard to imagine the political unrest that will exist in most of the world when hundreds of millions of people lose everything they have, homes, jobs, cars, food, lives. So no one thinks about it today! As long as companies keep making larger and larger (short-term) profits, and keep hiring enough employees, nothing will change. It is a truly sad consequence of modern technology and modern attitudes.
Interestingly, the few leaders who even see a problem all seem to assume that modern technology is so advanced as to be able to easily solve even this problem. However, there really is no "high-tech" solution available, except possibly to make trees and other plants even better at what they do naturally, the process of photosynthesis. But even that only represents a short-term effect, because of there then being even more organic material that has to die and decompose! Someone will probably eventually come up with the idea of covering all the oceans with some sort of fast-growing oxygen producing algae or some other similar plant. And the problem will then be likely to be so desperate that it will be instituted, without ever considering any long-term consequences. Even if such a concept worked to straighten out the carbon dioxide gas matter, it figures that more, possibly even worse, consequences might then result! It seems highly likely that such an effort would quickly totally kill all the fishes ane everything else in the oceans, and most competing plants, too, so the oceans would wind up totally dead-zones after such an experiment. Human beings are an interesting lot!
Political leaders go on television to announce that they WANT to get their country to commit to a 20% reduction of CO2 emissions by the year 2050! They seem to be oblivious to facts! By 2050, there will be NO petroleum left in the ground, anywhere on Earth. There will be virtually NO natural gas left. There will be NO Uranium that could be mined anywhere. (there WILL still be coal!) So such a statement might seem to be implying that he is caring, and that might be true, but it is the emptiest of all possible statements, because of the facts. The reality will certainly be that, by lack of any fuels, the emission into the atmosphere of carbon dioxide will be nearly completely ended! NOT by any political or business decisions, but by total lack of being able to proceed with the status quo!
Given the rate that China and India are using up those fuel resources (new electric power plants are completed EVERY WEEK!), the projections regarding supplies of fuels lasting (see the Current Energy Resources link below for official government and industry figures) will certainly be far shorter. Nearly complete consumption of all the world's petroleum, natural gas and nuclear seem likely by around 2020, less than 15 years from now! Almost certainly by 2030. AFTER that point, we really will no longer even have the CAPABILITY to send much carbon dioxide into the atmosphere, so THIS problem will disappear because a natural situation, total lack of fuel!
This figures to be especially interesting to watch, as Washington, D.C. is at 25 feet altitude right now! Certainly, within 30 to 50 years, that entire city will be gone and part of the Atlantic Ocean! I bet that the Senators and Congressmen will start really enacting effective laws when there is a foot of water in their offices, within just a few decades! (The Washington Monument may appear to be a lone tower sticking out of the ocean, hundreds of miles from any land!)
The recent concern regarding trying to save New Orleans will be entirely forgotten, as New York City (55 feet), Baltimore (100 feet), Boston (20 feet), Philadelphia (40 feet) and most of the State of Florida, all figure to be underwater within just a few decades. There are liable to only be around 30 United States which may still actually exist 140 years from now! (But some will still be islands, where mountains now stand. (Only 15 States seem unlikely to lose significant area in this process.)
This discussion did not include the effect of the change of seasons. In winter (in the Northern hemisphere), the sunlight comes from a lower angle in the sky, so it has to pass through a longer path through the atmosphere, so all those loss effects described above are greater. Also, with the sunlight hitting the Earth at an angle, the light is spread out over a larger area, so any specific (horizontal) area gets less incoming heat. So, even though the Earth is closest to the Sun on January 3 each year, that lower incoming angle (due to the tilt of the Earth's rotation axis) causes less incoming heat during winter and so cooler weather.
All these matters are very complex, and each is the subject of many textbooks! The fact that these are so complex a set of subjects is the normal excuse that businesses and politicians use to still try to deny the very existence of global warming! If and when they ever have to face the reality of the effects they are causing (in their pursuit of short-term profits), they would be forced to also confront the long-term catastrophic consequences of their activities. Interesting, it seems almost certain that the long term financial costs (having to completely replace all the major cities of the world, etc) will be far greater than the total of their short-term profits now! But since those consequences will be faced by businessmen and politicians of 50 and more years from now (AND NOT THEM!), they do not see any real reason to care! I am an advocate of technology, but to see technology used and abused in such terrible ways is really disgusting (personal opinion!)
But this was the first time that any large group like that has admitted that the effects of greenhouse gases (which they say are definitely the cause of the global warming, and that WE directly have done it), will continue for HUNDREDS OF YEARS and possibly THOUSANDS OF YEARS. No one yet seems to realize the importance of that statement. IF we cause the average Earth's temperature to rise by the (VERY conservative, and they admitted that) 4°C (which is about 9°F) by the end of this century, and if we KNOW that the temperatures will continue to rise for hundreds or thousands of years after that, some day, someone will realize what that means! We will have exterminated countless species of animals, maybe even ourselves, because they can't deal with those very high temperatures, and if we cause places like here in Chicago to be 100°F in winter and 180°F in summer (speculating, for maybe 500 or 1000 years from now), even humans may have trouble surviving!
They mentioned another comment that closely matches what I said in this web-page several years ago. They were ONLY talking about the ice sheet in Greenland, which is melting at the amazing rates described above, where about 150 feet wide sections of the edges of the Greenland ice are falling off every single day. They noted in their report that if all of the Greenland ice sheet should melt, that will raise the world's sea level by about TWENTY-THREE FEET!
In a somewhat strange loss of logic, their report seems to indicate that nearly all of Greenland's ice will be gone by 2100, but they then indicate that the oceans are likely to rise by just few feet! Didn't they even read their own report where they clearly state that the direct effect of just Greenland's ice melting will result in a 23-foot rise in all the oceans? I must be missing something here!
For the record, any map can show that Greenland has an area of around 2,170,000 square kilometers, of which 1,834,000 square kilometers is ice cap, which has an average thickness of about 1.4 kilometers. Multiplying that area and thickness and we get a volume of about 2,570,000 cubic kilometers of ice. The oceans of Earth total around 361,000,000 square kilometers of area. Dividing, we see that adding that VOLUME of ice to the oceans would add 0.0071 kilometer of water depth to all the oceans. This is just over 7.1 meters or the 23.3 feet of added depth to all the oceans, that even THEY agreed will happen.
They SAID that nearly all of Greenland's ice will have melted by the year 2100, but then they said that all THAT melting PLUS all the melting of Antarctica will only raise sea levels by ONE FOOT. Even as of 2008, the common claim was that melting glaciers will cause ONE foot of sealevel rise; the expansion of the waters of the warmer oceans will cause another ONE foot of rise, and the collective melting of Greenland and Antarctica Ice Caps will cause a third ONE FOOT RISE, so they claimed that by the year 2100, sea levels will rise by a total of THREE vertical feel. In the SAME Report, they STATED that just Greenland melting will cause a 23 foot rise, AND that Greenland WILL all melt by 2100, but then they conclude that BOTH Greenland and Antarctica will only cause a ONE-FOOT RISE by 2100. I have a suspicion that they realized that the public would be panicked if they publicized a 23-foot rise of the oceans, and so they somehow justified saying a ridiculously smaller amount, actually only about AN INCH due to Greenland!
Look on a globe at how small Greenland is, especially as compared the HUGE Antarctic ice sheet (about nine times the area). If they are discussing the world's oceans rising 23 feet just from Greenland, can you see that the above (simple) calculations are certainly true, that Antarctica melting will cause that 260 to 310 foot rise? And there are many other glaciers and ice sheets, like on most of northern Siberia, Alaska, Norway, Sweden and Canada.
Their report announced that sea levels will rise by at least four feet by the end of this century. But they also admit that is the most conservative of the conservative possibilities.
So, in publicized claims made in 2004, the claim was a MAXIMUM of one millimeter per year (or 4 inches during the century), which they then increased by a factor of 12 for their 2007 Report, up to 4 feet total rise during the century, but they already admit that just Greenland will cause a 23-foot rise in all the oceans during this century. But then consider Antarctica. We showed above that maps and radar and sonar soundings show that there are around 28,500,000 cubic kilometers of ice on Antarctica. Doing the same division as above, we see that if all the Antarctica ice cap melts, that represents 0.079 vertical meter of added water to all the oceans. That is 79 meters or 258 feet vertical rise of the world's oceans.
Simple math shows that the reality for the year 2100 is likely to be around an ocean sea level rise of 258 feet plus 23 feet plus around 16 feet from all the glaciers melting plus around 45 feet due to the warmer ocean water expanding, for a total increase in the height of the world's oceans at around 343 vertical feet. Credible other estimates can be made which total closer to about 430 vertical feet. Tha majority of the major cities of the world were built near sea level, and they ALL figure to be hundreds of feet submerged under the oceans, at a time when small children living today might still be alive! As to Washington DC, nearly all the important buildings will likely be GONE under the ocean, with only the top half of the Washington Monument visible, and possibly a small portion of the dome of the Capitol Building. Those two will then likely be hundreds of miles away from any land!
My personal guesstimate is that sea levels will already be four feet higher than today by 2025, less than 15 years from now! And that by 2050, at least 15 feet and probably more than 20 feet higher than today. And by the end of this century, at least 60 feet and possibly 150 feet higher than today. Nearly EVERY major world city is lower than that! It is good that people are finally at least starting to realize what we humans have done.
I realize that there are readers who will completely disbelieve such comments, and attribute them to some "lunatic tree hugger" However, I am not that. I am a Physicist, who does not really care about political and social consequences of research I do, but instead simply insist that it be as accurate and complete and correct as it can possibly be. My intent here is NOT to be "alarmist" or a "the sky is falling catastrophist". It seems that is the case, but these statements here are all scientifically based and likely to be reliably true.
It is appropriate to note something else here. Petroleum was only discovered around 1870, and only rather small amounts of it were pumped up and refined before around 1950. So we have really done all of this SINCE 1950! And, today, we (the whole world) are wildly burning everything and anything we can find as fast as we can burn it! I mention that here because that report noted that the EFFECTS we are seeing today are actually due to greenhouse gases put into the atmosphere before around 1970. They were rather quiet in their reference that things will certainly get much worse. In other words, their very grim report of today is certain to be spectacularly outdone by climate changes in twenty or thirty years, which no one can even estimate yet. In other words, they were essentially saying that "we are TELLING you that sea levels will rise by four feet, but that we actually know that things will actually become far worse."
Their report also made clear that nothing can now stop this happening, that the best we can hope for is to get the effects to slow down after 2050 IF we greatly stop today. Well, they have to know that we are NEVER going to STOP today! Or ever, until it all runs out!
THIS is one subject that I REALLY would have preferred that my calculations from the 1970s and my comments then (which were all absolutely ignored!) and even this web-page of 2004, might have all been wrong. But since human societies are NOT going to show restraint regarding burning fossil fuels, the locomotive is going to go off the cliff at quite high speed. And there are so many bad consequences that it is terrifying.
Yes, there are some caring individuals who will turn out light bulbs or such things. But at the same time, there are over a billion Chinese who are just now learning to get spoiled like us, AND they suddenly have loads of money to spend. So for each person here who turns off that light bulb, there will be ten in China buying the biggest and the most expensive cars, appliances and everything else. China doesn't know it yet, but they are likely to only have a total of ten or fifteen years max of prosperity before all the major energy sources are gone (petroleum, natural gas, Uranium/nuclear) and they will have serious crises of their own then. It does NOT figure to be any 'fun time' anywhere in the world even twenty years from now. WE did that! We can't blame it on dogs or cows or trees!
C Johnson, Theoretical Physicist, Physics Degree from Univ of Chicago