How concerned should we be about climate change? Threats such as ISIS, ebola and shaky economies seem much more immediate and tangible than global warming. We asked two of Tech’s top experts in the field to discuss the issue.
Uncertainty Doesn’t Mean
We Shouldn’t Take Action
By Judith Curry
At the recent United Nations Climate Summit, U.N. Secretary-General Ban Ki-moon warned that “without significant cuts in emissions by all countries, and in key sectors, the window of opportunity to stay within less than 2 degrees [of warming] will soon close forever.” The premise of dangerous human-caused climate change is the foundation for President Barack Obama’s plan to reduce greenhouse gas emissions. So, is there an overwhelming scientific justification for the premise of dangerous human-caused climate change and the urgency for immediate action? I am concerned that the problem and its solution have been vastly oversimplified.
The climate has always changed and will continue to change. Humans are adding carbon dioxide to the atmosphere, and carbon dioxide and other greenhouse gases have a warming effect. However, there is enduring uncertainty beyond these basic facts, and the most consequential aspects of climate science are the subject of vigorous scientific debate: whether the warming since 1950 has been dominated by human causes, and how the climate will evolve in the 21st century due to both natural and human causes.
There is growing evidence that the climate is less sensitive to adding greenhouse gases than has been predicted by climate models. Solar variability, volcanic eruptions and long-term ocean oscillations will continue to be sources of unpredictable climate surprises. Societal uncertainties further cloud the issues as to whether warming is “dangerous” and whether we can afford to radically reduce carbon dioxide emissions in the near term.
Can we make good decisions under conditions of deep uncertainty about climate change? Uncertainty in itself is not a reason for inaction. Research to develop low-emission energy technologies and energy efficiency measures are examples of “robust” policies that have little downside. It is in America’s long-term political and economic interests to develop a renewable alternative to fossil fuels. However, attempts to modify the climate by reducing carbon dioxide emissions may turn out to be futile. The hiatus in warming since 1998 demonstrates carbon dioxide is not a control knob on climate variability on decadal time scales. Even if carbon dioxide mitigation strategies are successful and projections are correct, any climate impact would not be expected until the latter part of this century.
Whether or not human-caused climate change is exacerbating extreme weather events, vulnerability to these events will continue—owing to increasing population and wealth in vulnerable regions. Climate change may be less important than rising populations, land use practices and ecosystem degradation. Regions that find solutions to problems of climate variability and extreme weather, and address relevant challenges of an increasing population, are likely to be well prepared to cope with any additional stresses from climate change.
Judith Curry is Professor in the School of Earth and Atmospheric Sciences at Georgia Tech, specializing in the dynamics of weather, climate and the atmosphere.
We Have to Start Paying Down
Our Climate Debt Now
By Kim Cobb
As a climate scientist, I firmly believe that if Americans understood the facts about climate change, they would be concerned enough to support a comprehensive, data-driven plan to reduce greenhouse gas emissions. Nobody with any knowledge on the subject denies that carbon dioxide (CO2) derived from the burning of fossil fuels is measurably warming the planet. Nobody denies that the risks of climate change will accelerate as greenhouse gas emissions accelerate. And nobody denies that, given the long lifetime of CO2 in the atmosphere, the climatic response of our current emissions will play out over the lifetimes of our children and our grandchildren. They will inherit our generation’s climate debt, and its accrued interest, potentially in the form of irreversible impacts.
Opponents of climate action cite grave uncertainties about the magnitude of future climate change impacts, but such uncertainties are two-sided. It is equally likely that future impacts will be less than or greater than those projected by climate models. So yes, there is a very small chance that climate change impacts will be relatively benign over the next century, with modest damages. But there is also a very small chance that those impacts will translate into economic “catastrophe”— in the jargon of economists who attempt to quantify climate change risks.
In this sense, inaction on climate change is like betting against the house when you know the deck is stacked in its favor. You might be willing to lose a few bucks for a small chance of a huge payout, but you wouldn’t bet your life’s savings.
For those who are concerned, it’s often unclear what, if anything, can be done to avert climate change. It is true that whatever steps we take today to limit greenhouse gas emissions, climate change will still accelerate over the next decades—the climate system and energy infrastructure both carry appreciable momentum.
But by the same token, the longer we wait to begin curbing emissions in earnest, the tighter we lock future generations into a path of accelerating climate change. For every year we delay, we accept (knowingly or not) that the stabilization level for greenhouse gas concentrations in the atmosphere will be ever higher, and the associated climate risks ever greater. The recent agreement between the United States and China to limit emissions growth over the next decades is an important down payment towards collective climate action, but the most effective action will come when each and every American understands that they have a role to play in reducing emissions.
The power of collective action is demonstrated during a class project in my “Energy, the Environment, and Society” course that I teach at Tech each spring. In the Carbon Reduction Challenge, student teams compete to reduce CO2 emissions over the course of two short months. The most successful teams engage with private-sector partners, and the savings they achieve are remarkable. One winning team averted over 180,000 pounds of CO2 emissions by recycling wooden pallets at a large manufacturing plant. That’s equivalent to taking 15 cars off the road for an entire year.
If each American began to rethink how they conduct their own “business as usual,” and that of their workplace, we could begin to pay down the climate debt while paving the way for a sustainable energy and climate future for our children and grandchildren. A collective effort to reduce energy use, when combined with the continued development and deployment of affordable, low-carbon energy technologies, puts such a goal in reach.
Kim Cobb is Associate Professor in the School of Earth and Atmospheric Sciences at Georgia Tech, specializing in paleoclimates, climate change and geochemistry.
Twitter
I have to side with Dr. Curry, there is no need to panic. It is prudent, however, to work to reduce human CO2 emissions by converting to less carbon intensive fuels like natural gas and eventually to nuclear. I have no problem with those who say we should be mindful of human impact on climate, but those like Dr. Cobb who throw around terms like “irreversible” and “catastrophic” are exceeding the bounds of knowable science. Having your students try to lower their own CO2 emissions can have only a trivial impact on overall human emissions and smacks of feel good activism. If you want to have a significant impact promote clean energy technology in the developing world (and I don’t mean windmills and solar panels).
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This piece is getting some discussion on Curry’s blog, posted today:
http://judithcurry.com/2014/12/13/week-in-review-32/.
Any article that attributes controversial facts, such as AGM, to “nobody with any knowledge of the facts” is writing about a political position, not science. This is particularly obvious when the other scientist in this article disagrees. The propaganda continues with the usual “scare ‘em and sell ‘em” technigues including leaving a carbon debt to our children.
The warmist “scientists” are funded by billions of dollars in grants and subsidies, and they are defending their turf in spite of mounting evidence that the real driver of the climate is the sun, not CO2. Furthermore, they never mention that CO2 effects saturate out on a logarithmic scale, and that doubling CO2 will increase heat entrapment by only a few percent. CO2 is chosen as the victim gas, even though it is measured in parts per million, because of the carbon tax, which supports the grant money.
Not a penny of this carbon tax goes to any real technology that might actually change our dependence on fossil fuels. such as thorium reactors, fusion, or off-grid local power nets. The carbon taxes are grants to sympathetic warmists and, on the international level, a redistribution of wealth to emerging countries.
It’s a tax, not a fix, folks.
” given the long lifetime of CO2 in the atmosphere,”
This says otherwise.
Friday, August 9, 2013
Paper finds lifetime of CO2 in atmosphere is only 5.4 years
A paper presented at the SEVENTEENTH SYMPOSIUM ON THERMOPHYSICAL PROPERTIES finds that the lifetime and residence time of man-made CO2 in the atmosphere are only about 5.4 years, far less than assumed by the IPCC. The paper corroborates prior work by Salby , Humlum et al , Frölicher et al , Cho et al , Calder et al , Francey etl , Ahlbeck , Pettersson , Spencer , Segalstad, and others which has demonstrated that man-made CO2 is not the primary driver of atmospheric CO2.
http://hockeyschtick.blogspot.co.uk/2013/08/paper-finds-lifetime-of-co2-in.html
There is a (possibly intentional) confusion here. What is claimed to have a long lifetime is actually the supposedly elevated levels of CO2, not the individual molecules. Given the huge natural flux in CO2, with roughly a fourth of the total atmospheric mass being exchanged every year, most molecules emitted by humans or natural sources are gone in just a few years. But the elevated CO2 levels do not consist of human emitted molecules, rather they are claimed to be caused by our emissions. The hypothesis is then that even if human emissions quickly went to zero the elevated levels would take centuries or more to completely dissipate. It is this long (and conjectural) dissipation time that is being referred to, incorrectly, as the CO2 lifetime. It makes it sound like CO2 is a long lived pollutant, which it is not.
The carbon in wood pallets comes from the air, not from fossil fuel, and is part of a biological cycle, not a geological cycle. Humans raise net atmospheric CO2 concentration only when they release fossil carbon (coal, oil, & fossil gases) into the atmosphere, mostly by burning. Burning or decomposing wood has no net effect on atmospheric CO2 concentration.
Larry Barden
The phrase “a plan to reduce greenhouse gas emissions” could have two meanings. If it means, emitting less greenhouse gas than would have happened without the plan, that’s one thing. But, if it means that each year’s emissions would be lower than the prior year’s emissions, then I would say there are no such plans. IMHO CO2 emissions won’t actually fall until we develop a non-carbon-based source of energy that’s as cheap as carbon-based energy.
But Professor Cobb, Dr. Curry states clearly “However, there is enduring uncertainty beyond these basic facts, and the most consequential aspects of climate science are the subject of vigorous scientific debate”. The two basic facts agree upon are “The climate has always changed and will continue to change. Humans are adding carbon dioxide to the atmosphere, and carbon dioxide and other greenhouse gases have a warming effect.” If the two of you agree on only these two facts — along with nearly everyone else, even those labelled “climate deniers” — then there is indeed a great deal of serious scientific disagreement. I’m afraid your “Nobody”s are actually quite a few leading climate scientists.
Unfortunately the skeptical side of this debate is missing. Cobb is what is called a warmer and Curry a lukewarmer. Their main difference is in how serious the threat is. Skeptics, some of whom know a lot about the science, argue that a threat has yet to be proven, and may not exist, so no serious action is called for. Many have concluded that the CO2 increase probably has no measurable effect.
I don’t understand why we are even debating this. If there is enough evidence that warming is happening (there is), and there is great concern that we humans are contributing to this (there is), then why aren’t we RIGHT NOW, changing the way we do business with the planet? If we have the ability to slow down and even reverse the changes over time, no matter what the cause, why aren’t we working together to do this?
We’ve been arguing about this for over 50 years. It appears to me that the biggest obstacle in the way of our making a difference is the money Big Oil is putting into our political system. Things are already changing for the worse, and the band plays on….
First of all, some warming is good, including the low end of the model estimates. No one wants a return of the Little Ice Age. Second, it is far from settled whether humans have had very much to do with the small warming that has occurred. This is called the attribution problem. Thus the debate is over, and due to, speculative predictions of harmful warming due to human activities. This is one of the great scientific and policy debates in history and it is far from over.
As for money, both sides are putting plenty into the debate, just as with the elections. Policy is an adversarial process. But the debate does not exist because of the money, quite the opposite. It exists because the science is inconclusive and people differ as to what that calls for.
Beign an IE, I have a different take on the issue. Resources are limited. A much larger risk to the health of our children, that is more certailn, is the astronomical debt the US continues to pile up.
I am conservative but see both parites at fault. We cannot afford to spend resources to fix greeen house emissions when if we do not deal with getting our spending in balance. The severe depression the world sees from inaction there will fix the problem with green house gases as consumption will dry up.
The rise in oil prices has done more to cut emission and promote alternatives than any govenrment regulations. A simple way to deal with immediate issues and help this is by increaseing the tax on fuel as the cost of oil falls below say $60 per barrell. I do not like taxes but we should not worry about green house potential disaster while certain disaster is starring all us (Democrat & Republican) in the face. The recent drop in oil price threatens cleaner alternatives like natural gas, but it can provide a tax source that can help both issues without GDP threats.
Bottom like on the two opinions is we do not know who is right with certainty, but we cannot afford to fix this potential issue when a more dyer one is not dealt with.
I find myself firmly in the skeptics camp. Elitist arguments are galling, especially in the government war on weather. The failure to release uncompensated temperature data, restricting access to taxpayer paid research to a priesthood smells like rat. I’m old enough to remember when global cooling was on the cover of Time. I’ve read enough of the modeling problems with clouds and read enough about mathematical chaos to suggest that there are real limits to human knowledge and system predictability in the face of chaos. Using a few non linear differential equations in a simulation as a predictive tool is a dicey affair. Attempting to model life itself planet wide should define hubris.
A quick peek at wikipedia gives scale to the problem of modeling the atmosphere that is so many orders of magnitude less massive than the water, land, and life that it interacts with.
No one asks if you believe in gravity. AGW is politics first, science a distant second.
All of the debate and argument over “climate change” seems misplaced IMHO. At issue here is the impact of increased atmospheric CO2 upon oceanic acidity. It is well established that increasing the level of atmospheric CO2 will decrease the pH of the oceans. See e.g.
http://en.wikipedia.org/wiki/Ocean_acidification
Most of the effects of lowering the pH of oceans are detrimental to marine life, which is one of our major food sources. We should be more concerned about upsetting the marine ecology and destroying the fishing industry than what happens to our climate.