With all the misinformation and hysteria surrounding global warming, the truth is badly needed. Here are the important facts about global warming presented in a question and answer format. Documentation for the answers can be found in the articles concerning global warming previously linked on this blog.
THE DEBATE OVER GLOBAL WARMING
Is there a scientific consensus about global warming?
No. Over 31,000 scientists, including over 9000 PhD holders have signed a petition opposing the alarmist view on global warming.
Didn't Al Gore's movie settle the issue?
Gore's movie is filled with errors and unsupported claims. A court in Britain found that it contains eleven proven errors and prevented it from being shown in schools without warning of this. It contains a cartoon of a polar bear drowning, while in reality polar bears can swim. It claims that sea levels will rise 20 feet, while even the alarmist IPCC says the worst case scenario is an increase of 19 inches.
IS THERE GLOBAL WARMING?
Hasn't Earth warmed over the past century?
Yes, a little. Earth warmed a little 1900-1940, cooled a little 1940-1975, warmed a little 1975-1998, and has stayed constant 1998-2008. All of these charges were less than one degree.
How much has Earth warmed?
Alarmists say that Earth has warmed one degree, while skeptics say it has warmed one half degree.
Why the difference?
Measuring global temperatures is complicated. The collapse of the Soviet Union shut down many measuring stations there. Many stations in America are not located according to guidelines. For example, one is located near an air conditioning exhaust vent. The urban heat island effect means that urban areas are warmer due to development, which can skew the results.
IS GLOBAL WARMING GOING TO GET WORSE?
One degree isn't very much. Isn't the planet going to get much hotter?
That's what alarmists say.
Is this prediction based on science?
Not exactly. It is based on computer models. That may sound scientific, but a model isn't necessarily correct. There are good models and bad models. Models can be retrofitted to existing data.
How can we tell if models are accurate?
The test of any model is whether it makes good predictions. A model can both be made to fit existing data and predict anything.
Do global warming models make good predictions?
The really dire results predicted by these models always seem to be 10-20 years in the future, too long to wait. But this question can be answered thanks to the fact that the non-warming of the past decade has led alarmists to predict no more warming before 2015. If their models were reliable, they should have been able to predict this before the non-warming was evident. The fact that they didn't strongly suggests that their models are not reliable.
IS GLOBAL WARMING CAUSED BY HUMANS?
What do alarmists say is the cause of global warming?
They say that it is due to the increases in emissions of Carbon Dioxide (CO2) due to human industrial activity. There is more CO2 in the atmosphere than in recent centuries. CO2 is a greenhouse gas, which means that when sunlight enters the atmosphere and reflects off the Earth, some of it is reflected back to Earth, making the planet warmer than it would be without an atmosphere. This is called the greenhouse effect. They say that increased CO2 has led to increased warming.
Is this explanation correct?
It is certainly true that human emissions of CO2 have increased. And the greenhouse effect is real enough. Without it life could not exist on earth.
Are there any problems with this explanation?
Yes. For one thing, CO2 isn't the only greenhouse gas. Water vapor is a far more important greenhouse gas. For another, the increase in CO2 in the atmosphere is not necessarily due to the increase in human emission of CO2. That may sound strange, but realize that CO2 doesn't simply stay in the atmosphere forever after it is emitted. It is taken out of the atmosphere by plants, which use it to grow. Thus it is reasonable to suspect that if more CO2 is staying in the atmosphere, there is another reason.
Isn't the level of CO2 in the atmosphere correlated with global warming?
There is a correlation. But correlation is not causation. When there is a correlation of A and B, A could cause B, or B could cause A, or both could be caused by another factor C. Further, the historical correlation shows that CO2 levels lag global temperatures. This means that they cannot be causing them, and it suggests that higher temperatures may cause higher levels of CO2.
How is that possible?
There is a large amount of CO2 contained in the oceans. When they warm, more of it is released into the atmosphere. When they cool, they absorb more of it back.
Hasn't temperature gone up along with human CO2 emissions over the past century?
The correlation is weak. As seen above, there have been periods of both increases and decreases in temperatures, while CO2 levels have increased steadily. The exception to this was when human emissions dropped during the Great Depression of the 1930's, when temperatures were the highest in the twentieth century.
Is there another explanation for the changes in temperatures?
Yes. The sun. The sun is responsible for the energy that keeps us alive. The alternative is that the sun's energy output changes slightly, resulting in changes in Earth's climate.
Isn't Earth the hottest it has ever been?
No. Earth was hotter than now during the Medieval Warm Period, long before human activity could possibly have affected the climate.
Is there a way to tell whether changes in solar energy output or human activity is responsible for current warming?
Yes. If the sun is responsible, we would expect to see warming on other planets and moons in our solar system. And we find exactly that--warming on "Mars, Jupiter, Pluto, and Triton". Humans cannot be responsible for that, so there is no reason to think that we are responsible for the warming on Earth.
IS GLOBAL WARMING A THREAT?
If there is significant global warming, wouldn't this be destructive?
There have been all sorts of dire scenarios suggested surrounding global warming. Given the unreliability of global warming models, such scenarios aren't too credible. Nonetheless, it is reasonable to suppose that global warming would have some negative effects.
Then shouldn't we implement measures to stop it, just in case?
No. Global warming would also have positive effects. Predicting specific effects is difficult, but there is no reason to think that all such effects would be negative.
Can you tell whether the net effect would be positive or negative?
There is good reason to think that the net effect would be positive. During the Medieval Warm Period, roughly 800-1300, temperatures in Europe were warmer than they are now. This was a time of prosperity relative to both before and after due to such factors as higher crop yields.
Is there a concrete example of a positive consequence of global warming?
Yes. Fewer people will die from cold. Since cold kills far more people than heat, there would be a significant net gain.
Would global warming melt the polar icecaps and flood the coasts?
No. As noted above, even the alarmist IPCC says the worst case scenario for the rise in ocean levels is 19 inches. This is hardly a nightmare scenario.
IF GLOBAL WARMING IS A THREAT, HOW CAN IT BE ADDRESSED?
If global warming is a threat, should we implement the Kyoto treaty or some sort of "cap-and trade" system or carbon tax to deal with it?
No. Even if global warming were a real threat caused by human CO2 emissions, the Kyoto treaty would not work because it only applies to some countries. It exempts China, India, and many other third world countries. China is now the largest CO2 emitter. That's bad enough, but if drastic CO2 limits were implemented in America, manufacturing would be outsourced to China and other such countries, meaning that total emissions might not decrease at all.
But shouldn't we reduce carbon emissions just to be safe?
No. The world economy depends on them. Major cuts in carbon emissions would cause a massive increase in poverty, millions of job losses, and major decreases in quality of life and life expectancy.
But isn't cutting carbon emissions the only way to stop global warming?
No. There might well be a technological solution. For example, some people have proposed putting mirrors into space that could reflect some of the sunlight coming to Earth. Others have proposed putting particulate matter into the atmosphere to reflect more sunlight. This is not to say that these plans would work or are good ideas, only that there could well be a technological solution, and poverty isn't the only option.
What if there isn't a technological solution?
Then we should deal with global warming the best we can. We will be able to do this far better if we are rich than if we are poor. There is a reason that earthquakes of equal magnitude kill thousands in the third world but only a few in America. Natural disasters can best be mitigated in affluence.
Can't global warming be mitigated without major economic damage by finding alternative energy sources?
The trouble with all the usual alternative energy sources is that they don't produce much energy, and they produce it far too expensively. In any case, the best way to find an alternative energy sources is through the free market, not government mandates.
Isn't there any significant source of inexpensive energy that doesn't produce carbon emissions?
Actually, there is. Namely, nuclear energy. Nuclear energy is cheap, efficient, and doesn't create any carbon emissions. If the alarmists really wanted a solution to global warming without major economic disruption, they would advocate major increases in nuclear energy.
THE DEBATE OVER GLOBAL WARMING, AGAIN
Why do many scientists say that global warming is real and a significant threat?
Consider how this situation came about. Climatology is a small field. To succeed, scientists need to publish research, and to do that, they need to get research grants. Those grants come from the government or major foundations. But the grant-making agencies are controlled by environmentalists who believe in global warming. Thus skeptics are unlikely to make it as climate scientists, and scientists have to endorse the alarmist view if they want to keep getting funding.
Isn't the United Nations Intergovernmental Panel on Climate Change (IPCC) the final authority on global warming?
Given the UN's record of corruption and incompetence, it should not be considered an authority on anything. The IPCC is "intergovernmental", meaning that its members are appointed by governments, which have their own agendas. Many members are computer modelers or statisticians, which may not be what people think when they hear of scientists. Further, the scientists listed in the IPCC report were not those who agree with the report, they were those "consulted" in the process of producing it. French scientist Paul Reiter had to threaten to sue to get his name removed from the report. The "summary" of the report, which is what most of the media read, was written by bureaucrats, not scientists.
Do environmentalists have a track record of accurate predictions in the past?
Quite the contrary. They have a history of repeatedly making doomsday predictions that have been proven wrong by the passage of time.
Don't environmentalists have our best interests at heart?
No. They want there to be fewer people and more poverty. See these quotes to find out their real agenda.