In the 1800s America supported an incredible variety of animal life at densities now almost impossible to imagine. Mega-flocks of passenger pigeons containing billions of birds stretched a mile wide and 300 miles long. Millions of bison roamed the Great Plains.
The passenger pigeon is now extinct, wiped out by hunting and loss of habitat. In 1914, the last bird, a female named Martha, died alone in the Cincinnati Zoo. The bison have largely disappeared but for a few small herds. These magnificent animals did not die of natural causes. They died because we humans failed to understand our massive impact on the environment.
With our technologies and immense population, humans beings are now a force of nature, capable of reshaping continents and creating holes in the ozone layer. Now we are actually changing the very climate of the earth by conducting an uncontrolled experiment with the atmosphere. We burn billions of tons of fossil fuels yearly, and release gases into the air as pollution: dirty particulates, sulfur and nitrogen oxides, heavy metals, and especially carbon dioxide.
Naturally occurring amounts of carbon dioxide keep the planet warm enough for life. Our additional contribution, however, has thrown things out of whack. Imagine a thick comforter covering the surface of the entire world. Every year we add another blanket, trapping even more heat. This is, in a nutshell, the cause of growing climate instability and change.
Solving this problem would be difficult enough on its own because of the importance of fossil fuels to our current economies, but adding to the challenge is a powerful chorus of science-denying politicians, interest groups, and "institutes" representing polluting industries for whom science is less important than ideology. Their goal is to sow uncertainty and confusion in the minds of the public and policy makers and to delay actions to address the problem. Small wonder Americans are confused about what to believe.
There is certainly a lot of confusing information out there, but truly interested readers can sort out opinion from fact. The challenge is having an open mind, rather than seeking support for pre-determined opinions. If you believe the earth is flat, think the sun goes around the Earth, or that the moon landing was faked, you can find "evidence" and support on the Internet.
But if you are truly confused about climate change, trust the scientists and the science, not radio and television talk show hosts, Las Vegas magicians, or representatives from organizations whose salaries depend on breeding controversy and fomenting uncertainty. Independent scientific associations, national academies of science, universities, and other unbiased experts, deserve our close consideration. Science changes, and scientists are sometimes proven wrong, but that is the scientific process itself. No climate denier has ever produced a better scientific theory that fits the actual science, observations from around the world, and evidence from the most sophisticated computer assessments on the planet.
As a famous statesman once said, "Every man has a right to his opinion, but no man has a right to be wrong in his facts."
With those caveats in mind, it's quite possible to draw accurate conclusions about climate change and the most popular attacks on it.
Scientists agree that climate change is happening, largely due to human activities.
No major or national scientific institution in the world disputes the theory of human-caused climate change. According to a 2010 study from the independent Proceedings of the National Academy of Sciences, over 97-98% of the scientists working in disciplines contributing to the study of climate agree that climate change is real and largely caused by human beings. This agreement is called a consensus, and the same consensus exists when scientists talk about the theory of relativity or evolution. In other words, the evidence for human-induced climate change is so strong that serious scientific disagreement with it simply does not exist. All of these scientists could, of course, be wrong, but until a satisfactory alternative explanation replaces it, we ignore the scientific community at our peril.
Scientists agree that climate change is happening faster than humans have ever experienced before.
The climate is changing rapidly, despite the desperate attempts of many science deniers to prove the contrary by cherry-picking data. One aspect of these changes is warming. The top ten hottest years on record have occurred since 1997, and the period from 2001-2010 is the hottest decade in recorded history. Measurements of the earth's total heat, including the upper atmosphere and the seas, and satellite measurements of surface temperatures show an indisputable rise over the last 100 years. But it isn't just temperature: further irrefutable evidence for warming comes from the observations that Arctic ice is thinning and retreating, massive amounts of ice are melting off of Greenland, birds are migrating earlier, permafrost is melting in Alaska and Siberia, and trees and flowers are leafing earlier, among many other examples. There is also growing evidence that climate changes are leading to increases in severe and extreme events, including rainfall, floods, droughts, fires, and pest outbreaks.
To be sure, the earth has been warmer in the past, but that warming resulted from natural causes and took thousands of years. The rapidity of our current warming trend is yet further evidence for the human fingerprint confirming our responsibility for climate change.
In the past few years, the public has been further confused by accusations that some scientists withheld data, or manipulated the types of measurements that prove warming. These claims come from the same fossil fuel industry-funded groups that are fighting hard to sow uncertainty and doubt. Seven independent reviews of these accusations carried out in Britain and America found that they are without merit, that the scientists' "rigor and honesty was not in doubt," and, most importantly, that the science itself remained unchallenged.
Modern society faces many threats, including new economic pressures, terrorism, wars, and more, and while growing instability in the planet's climate may seem to be a lesser concern, make no mistake: our world is changing rapidly, and our reactions now will determine the shape of humanity's future. If we do nothing, we commit ourselves and our children to an increasingly severe climate. Yet we are smart enough to tackle problems on many fronts at once. Effective solutions exist that can both reduce the threat of climate change while reinvigorating our economy.
Unlike the thoughtless extinction of the passenger pigeon, getting our response to climate change wrong will not simply result in a sad encyclopedia entry. We now sit where that unlucky bird once sat -- confident in our vast numbers with a disaster looming over the next rise. That future can be prevented, but the window for action is closing.