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Climate Change

Last chance to curb greenhouse gas emissions and climate change to limit catastrophic effects, international panel says

Policy responses to be discussed in December, methods to assess interactions of climate and innovation with economic growth win economics Nobel

by Jeff Johnson, special to C&EN
October 9, 2018


Credit: Technology Centre Mongstad
The U.S. Department of Energy is supporting three carbon dioxide capture projects at Technology Centre Mongstad.

The world faces a final opportunity to limit the extreme impacts of global warming, a key international science panel warned on Oct. 8 in South Korea. Successful intervention would require, however, “rapid, far-reaching and unprecedented changes in all aspects of society,” the panel said.

Global warming has already reached at least a 1 °C rise since the Industrial Revolution. That rise is driven by emissions of greenhouse gases, primarily carbon dioxide and methane, from human activity. Now a new report by the Intergovernmental Panel on Climate Change (IPCC) says the world is on a path to have its temperature rise 1.5 °C by 2030 and 2 °C by 2050 if people do not take swift action. This increase in global temperatures would have catastrophic effects, the report says.

A series of international agreements, stretching back to 2010, held the goal of limiting the rise of temperature due to global warming to 1.5 °C. This study, however, shows that goal is now unattainable without sweeping changes affecting land use, energy, industry, buildings, and transportation.

“Limiting warming to 1.5 °C is possible within the laws of chemistry and physics but doing so would require unprecedented changes,” said Jim Skea, cochair of an IPCC working group that prepared the report and a professor at Imperial College London’s Centre for Environmental Policy. Skea underscored an important role for scientists, particularly chemists, in reaching the needed reductions.

The IPCC report calls for greatly enhancing energy efficiency; expanding wind, solar, and nuclear energy production and energy storage; shifting from fossil- to electric-fueled vehicles; implementing carbon capture and storage; and ending coal use. Also needed are sweeping changes in agriculture, including implementing sustainable land-use practices, restoring ecosystems, and transitioning to less resource-intensive diets.

To curb global warming, by 2030 global net human-caused emissions of CO2 must fall by about 45% from 2010 levels and reach a net zero emissions level around 2050. These figures mean that any remaining emissions would need to be balanced by removing CO2 from the air through reforestation, land restoration, soil carbon sequestration, and direct air carbon capture and storage—an untried technology.

The report predicts grave climate change effects if people do not take action; it points to sea-level rise, coral-reef destruction, flooding, wildfires, extreme weather events, and famine. The impacts are particularly hard on the world’s poor.

The report reflects the fact that the nations of the world are already failing to make reductions they committed to in the 2015 Paris Agreement. The worst offender is the U.S., which plans to exit the agreement and has plunged ahead with plans to increase coal use and oil production. The U.S. is the world’s second-largest carbon emitter. But even if nations adhere to their Paris pledges, the expected temperature increase is 3 °C by the century’s end, the report says.

Governments attempting to implement the Paris Agreement asked the IPCC to create the report. At a press briefing, the IPCC panel members were repeatedly asked what governments should do. Deciding government actions was not their role, they answered, noting policy responses will be discussed in December at the Katowice Climate Change Conference in Poland.

Those policy responses will be informed, at least in part, by the work of William D. Nordhaus of Yale University and Paul M. Romer of New York University, who will share the 2018 Nobel Prize in economics.


Nordhaus developed a quantitative model integrating CO2 emissions, climate, and economic growth. His results suggest that global carbon taxes would be the most efficient method to curb greenhouse gas emissions.

Romer studies how innovation drives economic growth. His work shows that some government policies, such as research and development subsidies and patent regulation, are necessary to encourage new ideas and long-term growth.

Nordhaus and Romer have provided “fundamental insights into the causes and consequences of technological innovation and climate change,” the Nobel Prize announcement says. “Their findings have brought us considerably closer to answering the question of how we can achieve sustained and sustainable global economic growth.”


This story was originally published on Oct. 9, 2018, and revised on Oct. 11, 2018, for clarity.



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Steve McGovern (October 10, 2018 2:24 PM)
The following statement in the article is inflammatory and incorrect, "The worst offender is the U.S., the world’s second-largest carbon emitter, which announced it will exit the agreement and has plunged ahead with plans to increase coal use and oil production." The U.S. is not the worst offender. A quick search of the country pledges under the agreement reveals that China, the largest carbon emitter, did not pledge ANY actual reductions in GHG emissions.
Jacob Burke (October 10, 2018 2:37 PM)
According to trends among smokers, there were suppose to be 0 smokers in New York City by 2010. As anyone's high school level math book probably explained extrapolations are NOT valid considerably beyond the range for which there is data. A century is far beyond the valid time scale for predictions.

Second, There're variables we don't know about the climate--if there weren't, we would not being conducting climate research. Research is an admission that we don't know everything. So, there are climate variables we don't know. Among the variables we do know, there are ones we have absolutely no way to quantify; guessing values is not a valid substituent for measurement. Guesses reflect biases. There are additionally variables for which we do not know the interrelationships . And finally, there is the most important point of all, the word doesn't conform to our naive linear notions. Variables interact in complex ways, with positive and negative feedbacks, and we don't know all the mechanisms.

If you don't believe a fortuneteller, you shouldn't trust a climatologist. Predictions not validated by prior successes, are not facts, they are fictions. And in this case, fictions too often advanced for a political agenda.

As Dr. Feynman stressed so much, it so too easy to fool ourselves, and that is precisely what we are doing with climate change. I hope we don't repeat the inhuman atrocities as the eugenists a century before our time, who acted on just as much flimsy science as we do today on climate change.

Even if climate predictions were 100% valid, no model can predict the ingenuity of the human mind. Science should be about expanding the bounds of the possible, instead of running back into the dark cave of primordial beliefs, chief among which that Nature as we find it is eternal, unchanging and sacred. Let's be Darwinists instead.

lana (October 11, 2018 9:47 AM)
I once saw a line, and you could make a projection with that line, but it didnt come true....therefore all projections are false.
Yeah...thats about as accurate and useful as....
Jacob Burke (October 11, 2018 2:57 PM)
My point was that extrapolations, by their nature, assume all other variables to be constant. That is very, very dangerous to assume indefinitely into the future. No computer model has predicted 20-30 year climate change events. What grounds do we have to extrapolate on models that have failed over shorter time frames?

If you have experience with modeling, as I do, you would appreciate that models are simplified representations of reality by definition--not reality itself--and the models are only as good as the parameters used to build the model. Seeing as we can not even simulate accurate the dynamics of small biological systems at minute time scales, it is hubris to suppose that the climate can be accurately captured and projected 100 years hence. To think that is to be the conceptual bother of John Hammond in Jurassic Park--we can't engine the world to our climatological preference. We are not in charge. We are part of, and do not stand above, nature. That's the whole point of science.
Willy Sierens (December 22, 2018 5:13 PM)
Your arguments are correct. It's a waste of time and money to develop these climate models.
Instead it should be argued that the CO2 content of the atmosphere ramps up steadily due to human emissions (Keeling curve), and that the temperature also ramps up at an increasing rate (observation). Both can be linked through a plausible physical mechanism.

The rate of the changes is such that humanity won't be able to cope with them.
So it is prudent to stop emitting carbon.
That of course would stop modern human life in its tracks. (IOW everyone would be dead in short order).

So how to make the transition?

I for one don't know.

Ivars Jaunakais (October 10, 2018 5:08 PM)
Next month I turn 74. As a scientist I observe, even when I do not plan to observe. I observed that recent summers are a little warmer then when I was a boy. The meteorologists have confirmed this with temperature readings the world over. You can ignore my observation, but let’s not ignore the meteorologists. Should it not make sense to be conservative about the danger that may loom for us all? I suggest we immediately begin changes that will be definitely needed by 2100 to prevent major climate change. I don’t know if our world can ever avoid climate change, but our generation can avoid a really bad rap for being frozen by fear and lack of action!
Jacob Burke (October 11, 2018 2:50 PM)
Your experience of warmer summers is not necessarily wrong, but prioritizing more recent memories over older once is a well-known source of bias in psychological literature. Some of the warmest years on record at the 1930s.

Taking drastic steps may or may not be needed to avoid doom, but please do not assume that the risks are all on the side of not anti-climate change measures. Everything has risks, particularly when people imagine they can control what they don't understand. Again, if we understood the climate perfectly well, we wouldn't need climatology research. And the invocation of a linear model between CO2 emissions and temperature is completely not supported by the scientific literature. Nature is not a machine with simple inputs and outputs, and there is no temperature knob that we can simply turn.

Finally, climate change is a slippery term--if there is one thing the climate always does, it changes. Trust me, I live in New England. A theory that claims any change whatsoever is a validation for the theory is unfalsifiable , and is by definition, not scientific. If the only test for the theory is that the climate should remain perfectly the same, I'd ask when in pre-human history was that ever true?
lana (October 12, 2018 10:47 AM)
Everyone here knows the term climate change is the simplistic euphamism (for public consumption) for greenhouse gas based global thermal forcing, not the be-all of the underlying theory. Every climate scientist and the literature are very precise in investigating/confirming and then modeling/validating non-linear greenhouse-thermal forcing climate effects. Not understanding everything completely is very different than not having a pretty good idea. And when the effects are this catastrophic and the error bounds clearly deviate from anything experienced in modern human history...yes we have definitive greenhouse gas induced risk that probably (clearly?) outweighs the risks of not immediately reducing greenhouse gas emissions. Your comments are like critiques of a paper you never read when you overhear someone summarizing its contribution to a third paper. IPCC report is like a review of reviews, a Cochrans report on greenhouse gas forced climate change. Be skeptical all you want...but read the dang literature...all of it, before you make half cocked comments like this.
Robert Cassidy (October 10, 2018 7:44 PM)
Thorium LFTR reactors could take up a lot of the slack with inherently safer nuclear power. See articles and videos by Kirk Sorensen and others. Renewables have a place, but nuclear power has a much greater potential to displace meaningful amounts of fossil fuel power generation.
Ira Straus (October 11, 2018 12:20 AM)
There are two glaring fallacies in the policy side of this report. Both of them indicate a repression of urgent needed public discussion, and both of them contribute further to that repression:
1. The failure to advocate geoengineering in this era; the insistent reliance solely on emission reductions, no matter how extreme, no matter how unsustainable; and to keep upping the demands for emissions reductions when it's noticed that they ineevitably aren't effective enough. In reality, geoengineering is the only viable solution for now. It alone can reverse warming, and it alone can provide the time needed for doing drastic emissions reductions sustainably.
2. Its use of the line that we are facing imminent catastrophe, we have only a few years left to act, maximum ten years ---- yet if we act right now and just stop making more emissions, it'll be OK.

   I have heard this line issued in the manner of an official truth for at least twenty years. Logically, it could have been true for two years, but not twenty. That makes it self-contradictory. We can't every year for 20 years have had only 2, or 3, or even 10 years left.
    It is also self-contradictory immediately. The feedback loops (icecap melting, tundra thawing) are already underway. They make the reduction in further emissions-forcing inherently insufficient, even if we could somehow reduce emissions quickly to a net zero. At present temperatures, the icecaps and tundra will continue melting, feeding further warming. Only a geoengineering the global temperature back to a lower level can stop that.
The person who coined of the term Global Warming recently wrote, in the New Yorker, that the official line was PR nonsense; it is way too late for solving the problem by gradually reducing emissions; and honest people should stop fibbing and face the need for geoengineering. He showed that geoengineering was inevitable; the only question was whether we would prepare for it and do it in good time and carefully, or would avoid thinking about it and do it late and in desperation, without adequate testing and research. Alongside geoengineering, emission reductions would of course continue; geoengineering would give them the time they need so they can consolidate the climate stabilization.

   He was roundly attacked for being honest -- honest about geoengineering, and honest about the inherent fibbing of the entrenched, semi-official line. Attacked by what amounts to an orthodoxy that has controlled public discussion and prevented real discussion.

It seems obvious enough that geoengineering is the only method that can reverse the warming already underway and stop the feedback loops already in progress.  Even the most severe emission reduction plans don't pretend to do that. They only offer to slow the further forcing of warming, even while leaving the feedback loops intact --  and meanwhile run the global economy into the ground. How much destruction would that economic devastation involve? How many wars, revolutions and civil wars? How big a global firestorm, whose emissions would dwarf the emissions saved? Thus, the demanded plan doesn't actually address the problem at all. The problem can't be addressed without geoengineering.

   The repression of geoengineering has been enforced in the environmental movement by a kind of ideological fundamentalism, which is allergic to it and calls it "f___ing with mother nature". It is enforced on higher political levels by saying "there is no Plan B" (Macron). This is an anti-scientific fib; there are always Plan Bs. The main Plan B, geoenineering, is in fact known to Macron and others who use this slogan. The slogan, "There is no Plan B", has to be unpacked to be understood. It is in reality a way of stating that they and their political circles have a mental block against Plan B.
We will not survive unless we overcome the mental block.

William Rubin (October 11, 2018 11:24 AM)
More stupid global warming hype. People need to wipe away the BS from their eyes. This is just more "the sky is falling" drama to increase funding and people's paychecks.
William Rubin (October 11, 2018 11:55 AM)
This is in response to a comment made by someone who’s been brainwashed:

I once saw a line, and you could make a projection [extrapolation] from that line, and it came true [it was accurately predictive]…therefore all predictions are true.
Yeah, that’s about as accurate and useful as….

Grow up.
Jacob Burke (October 11, 2018 3:01 PM)
Rubin, the fact that you can not accept a mathematical trueism--that extrapolations have a prescribed range of applicability--and must resort to insulting the intelligence of someone by saying they are "brainwashed," only reveals your infantile ability to conduct a civil discussion. Scientists should be above this sort of name calling. Please, grow up.
William Rubin (October 12, 2018 10:29 AM)
Excuse me, but it seems you need a dose of growing up yourself. The global-warming community has been name-calling for years, and in this case, my "name-calling" was in response to belittling sarcasm - something you obviously overlooked. And, yes, many on the side of climate change refuse to look at alternative explanations and refuse to maintain an open mind. I accept extrapolations, when they are based on an accurate model, but you are assuming the extrapolations opposite climate change are accurate. Scientists should be above politics and close-minded assumptions. So, instead of impetuously responding to me in such a childlike manner you did, maybe you need to look beyond your own presuppositions and foul attitude and grow up.
William Rubin (October 12, 2018 11:06 AM)
How do you conclude that I don't accept mathematical truisms from what I typed above (Oct. 11, 11:55AM)? What I typed above was a "restructuring" of a comment by Iana who mocked your comments concerning predictability and climate change. It had nothing to do on whether or not extrapolations were true or false on the basis of a range of applicability. You stated, "extrapolations are NOT valid considerably beyond the range for which there is data" and "predictions not validated by prior successes, are not facts, they are fictions. And in this case, fictions too often advanced for a political agenda", and yet somehow criticize me for not accepting "that extrapolations have a prescribed range of applicability." That's a pretty surprising criticism based on the fact that erroneous extrapolation is one of my criticisms of the climate-change models - the current models' predictability is woefully inaccurate and characterized by false (or at least hasty) assumptions (my other major climate change criticism is politics). Thus, your criticism of not accepting " a mathematical trueism--that extrapolations have a prescribed range of applicability" would be best suited for Iana, who mocked your sentiment with a statement concerning extrapolation. So, I suggest you don't make false accusations against people (in this case that I can't accept mathematical truisms, e.g. that extrapolations have a prescribed range of applicability) prior to understanding the content and impetus of their communication.
Sahibzada Rashad Hameed (October 25, 2018 6:39 AM)
Undoubtedly global warming and its environmental impact are big issues and need to be highlighted. Unfortunately the subject is debated in conferences and papers to which common man has no access. Some people and organizations have to develop and run awareness campaigns to even every household for the major causes and their effects of global warming with discrete list of remedial measures that an individual, community or government functionaries could take so that the targets are achieved globally. Obviously the industrialized world has a bigger responsibility to share and cleaner production technologies have to be encouraged to minimize pollutants such as carbon emissions and other toxic effluents. We need to look at it at a much broader spectrum and use educational institutions for this purpose; grass root planning is required to attain well defined goals even at layman level.

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