The Climate "Debate"

Dr. Richard Nolthenius - Program Chair of Astronomy, Cabrillo College

The climate debate - Is the strong global warming of the past ~60 years due to human activities or not? But wait... is there really a "climate debate"? No. Not among climate scientists themselves. Global warming is strongly supported by the evidence to be human-caused. The idea that human-generated CO2 can change climate significantly dates back over 100 years. By 1990, data, computer modelling, and theory were solid enough to leave little doubt that human-generated fossil fuel emissions were changing climate and that it would accelerate. Since then, the widening disagreement between reality and climate models which neglect human causes has caused growing alarm and consensus that dramatic and urgent action is needed. More recently, 98% of working, publishing climate scientists support the conclusion that global warming is real (i.e. not just a wiggle in noisy climate records) and caused by human activities, mainly though fossil fuel burning, according to this analysis published in the Proceedings of the National Academy of Science (Anderegg etal 2010) . But, you say, we hear all the time on the news how controversial the issue is and it seems scientists are arguing fiercely about what is causing climate change - isn't it obvious there's a genuine debate on global warming's cause? No - the problem is that there are well-funded lobbying efforts by oil and mining corporate interests to get the public and the politicians to believe there's still a big scientific controversy, as a way to stall policy changes which threaten their profit streams. While there is a very active continuing research effort to clarify key climate processes, including modelling clouds and their feedbacks, the evidence strongly indicates that while these refinements will improve the error bars, they will not change the verdict. Depending on how that goes, the business-as-usual scenario will, by the end of the century, vary from being very bad, to being truly disasterous. There is no reasonable possibility that they will exonerate humans as the cause of the rapid warming that we're seeing. And therefore, that it is up to human beings to change, if they want to avoid disaster. I will justify that statement in this website.

If this were a resource page on purely astronomical understandings, there'd be no need to delve into politics and junk science. There's no corporate interests who feel threatened by what astronomers discover or conclude. Not so in climate research. Unfortunately, students cannot simply accept on trusting faith that what they hear in the media, or even in some classrooms, can be taken at face value.

I'll organize this website as follows: First, examing the politics and its connection to the unusually large amount of nonsense out there in the media, then the claims of those attempting to absolve human responsibility for global warming, and finally the evidence which convinces climate scientists that global warming is real, it's extremely serious, and it's caused by us. (AGW = anthropogenic global warming = global warming which is caused primarily by human activities, a useful abbreviation in what follows.)

1. The Politics of Climate

2. Debunking the AGW Denialist claims

3. The Key Evidence That Global Warming is Human-Caused

4. What is to be Done? Strategies

We have confirmation that the observed rapidly rising CO2 levels are coming from fossil fuel burning both from the known emissions rates, and from the unique carbon isotope ratio found in oil and coal laid down hundreds of millions of years ago (Ghosh 2003, and for the layman here). We know the physics of the Greenhouse Effect with very high precision, we know the distribution of CO2 around the planet and that it is throughly mixed on a short time scale, and that this physics leaves no doubt that man-made GHG's will cause warming of the troposphere and cooling of the stratosphere at levels consistent with real observations, even without complex climate models. We know that the denialists have provided not a single theory shown to be consistent with the observations, nor even a theory which pretends to be an explanation for what we have seen. At best, they have "well maybe..."'s, and as the science is against them, they attack the integrity of climate scientists and even the process of science itself. At best, they propose ideas or mechanisms which would affect modelling, but not an actual theory predicting what we, in fact, see. "Well, maybe"'s which, in fact under closer inspection are found to be in strong conflict with the evidence and the physics. We know that many millions of dollars of corporate money is being funneled to climate denialists and that their media and political connections have succeeded in dis-informing lay people, politicians, and even teachers who should know better, playing on their psychological tendencies. We know that this is especially prevalent in the United States, and that people in Asia and Latin America, for example, are much better aligned with the scientific consensus. As of 2009, only 36% of average Americans believe that global warming is caused by human activities, from a Pew poll. We know that there is already further warming of 1 degree Fahrenheit "in the pipeline"over the coming decades which will happen even if, impossibly, we stop all CO2 emissions instantly, due to the well understood thermal inertia of the ocean and its decreasing ability to absorb CO2 with increasing temperature. And we know that the relatively mild policy proposals so far discussed, including Kyoto, are inadequate to prevent economically and environmentally devastating consequences. And, we know that even these proposals can't get any political traction, due to the efforts of denialists (recent example: the CRU email theft just before the Copenhagen Climate Summit , and see the denialism of the Republican candidates of the 2010 election).

We need immediate and severe reductions in CO2 emission, a fact which is in such strong conflict with the desires of the Third World and Asia to raise their standard of living with available technology, that it may well take some catastrophic events unequivocally tied to global warming before world civilization will take the drastic steps required to prevent the worst consequences. Even more serious than climate change is the tragedy that CO2 is inflicting on ocean ecosystems due to CO2-induced acidification (links here, here, and references therein). Maybe this is a good place to repeat something I have told all my Astro lecture classes for 25 years at one point or another - Nolthenius' First Law: People Learn the Hard Way. Not all people, but unfortunately most are unable to make real and compelling enough within their own minds what the difficult truth is, and to support the necessary action.

Meanwhile, as the American public and politicians appear unwilling or unable to see through the fog financed by the oil and mining industry and face up to human responsibility for global warming, the rest of the world moves on. China, only recently having elevated itself out of Third World status, is already leading the U.S. in all measures of clean energy technology development and use, and by a significant margin. China is hardly a model world citizen, but they are not indulging in the self-deception that we are, here in the U.S.

A Few Degrees Warmer - So What?
You may think - "What's the big deal? Heck, I don't even know if I can tell when it's a couple of degrees warmer. Temperatures go up and down more than that every day of every year. Maybe I'll have to crank up my air conditioner a notch during summer, maybe we'll have to say good bye to a few species. It's not a disaster (After all, Richard Lindzen promised!)". What this naive thinking fails to grasp is that the world is adapted to a global climate which is disappearing far too rapidly - species cannot adapt when change happens this quickly. Species instead go extinct. A few degrees, held permanently, will melt all the ice of the poles, will cause mass die-offs of present forests and crops, will melt Arctic lakes and tundra with large reservoirs of methane, rapidly escalating warming still further. Countries will lose their most valuable and populated property - coastal property. Countries like Pakistan (a nuclear power, and not a very stable one) will lose a high fraction of its agricultural land, and a significant part of their entire country. Crops will fail as rain patterns change. Wildfires will become larger and more widespread, further adding CO2 to the atmosphere. Here in California, droughts will become more common and more severe. Rapidly rising CO2 will continue to be absorbed into the ocean much faster than it can be taken out by natural processes, raising its acidity and ruining the ability for calcium carbonate to form, which is the basis for a vast array of sea life which depend on this chemistry. The pH of the oceans have changed more in the last 150 years than in the previous several million years. This includes corals which form the habitat for 1/4 of all marine species at some point in their lives. Already we are seeing mass die-offs of coral reefs. Even using the conservative 2007 IPCC scenarios, within ~40 years the oceans will be too acidic for the survival of coral reefs, and they will disappear. At higher acidifications, all calcium carbonate-based species will perish. Here is a good introduction to anthropogenic CO2 and the dire consequences of ocean acidification. There are already serious reproductive failure among shelfish happening now. Climate change is rapidly destabilizing our ability to provide food for a still growing population. Already, revolutions are beginning, caused by famine.

What will be the response of civilization to this kind of rapid ecological change? World wars have started over much less. Fighting over desires or status is one thing. Fighting over food and water is another. The 6 C temperature rise which is now a serious prediction for the end of the 21st century, matches the global temperature difference between the depths of an Ice Age, and the warm interglacial of ~50 years ago. A few degrees is a very big deal.

A Final Comment
The first warnings of CO2-induced global warming date back a fully a hundred years. Denialism and oil/mining lobbying have combined with a science-ignorant American public to stone-wall the hard policy needed to drastically reduce carbon emissions and save what we can. Denialists continuously claim that strong action is premature, that more science is needed, that it's too costly to our lifestyle to think about significant reductions in CO2 emissions. This is absurd. Consider this cautionary tale: Merrill Lynch in 2008 used a few million dollars in extra bonuses to motivate its own brokers to buy billions of dollars of Merrill Lynch-created CDO's (collateralized mortgage debt obligations) which the market judged to be very low-value and high-risk, just in order to move these CDO's out the door. This essentially was committing suicide. Merrill Lynch, through its own short term greed for a few million dollars, destroyed itself - a 100 year old financial corporation once worth tens of billions of dollars. In the same way, the oil and mining corporations appear just as willing to do almost anything to keep just one more quarter of big profits coming in, even if it means long term disaster for our children. Climate scientists are receiving threats of bodily and other harm. There is the prospect of McCarthy Era -style inquisitions of climate scientists by the Republican-dominated House of Representatives (and here). The Arctic Ocean is projected to be only a few dozen years away from losing the last of its permanent ice. We are in the midst of the 6th mass extinction since life began on Earth, this one caused by humans - the Anthropocene Extinction, it is being called, with half of all species predicted to go extinct by the end of this, the 21st century. Given the overly conservative estimates on the loss of polar ice in the IPCC AR4 and the much faster environmental damage which observations are showing (see bottom of this page), many in the climate science community are afraid it may already be too late. That the tipping point has already been passed. If so, what a stupid and tragic legacy we are leaving to all future generations.

Other Resources

--Here's a great set of video programs covering in concentrated form the scientific case for human-caused global warming and a close look at the attempts to discredit AGW, from a prominent science writer.

--Prof. David Archer's Univ. of Chicago course Phy Sci 134: "Global Warming" in a series of mp4 lectures.
and below as a series of YouTube video lectures for the non-science major...
0 - Global Warming in Geologic Time (1hr 10min)
1 - Intro (11min)
2.2 - Heat and Light (50min)
2.3 - Blackbody Radiation and Quantum Mechanics (44min)
3 - Our First Climate Model (46min)
3.2 - The Greenhouse Effect (43min)
4.1 - What Makes a Greenhouse Gas? (45min)
4.2 - Greenhouse Gases in the Atmosphere (45min)
5.1 - What Holds the Atmosphere Up? (51min)
5.2 - Why It's Colder Aloft (45min)
6 - Wind, Currents, and Heat (50min)
7 - Ice and Water Vapor Feedbacks (35min)
7.2 - Clouds (48min)
8.1 - The Weathering CO2 Thermostat (37min)
8.2 - The Lungs of the Carbon Cycle (47min)
9.1 - The Battery of the Biosphere (43min)
9.2 - Coal and Oil (49min)
9.3 - Oil and Methane (44min)
10.1 - The Carbon Cycle Today (34min)
10.2 - The Long Thaw (41min)
11.1 - The Smoking Gun (46min)
11.2 - The Present in the Bosom of the Past (44min)
12 - Six Degrees (46min)
13 - Hot, Flat, and Crowded (13min)

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