Quotes from Experts

IPCC Working Group III report: Quotes from contributors

SciLine reaches out to our network of scientific experts and poses commonly asked questions about newsworthy topics. Reporters can use the video clips, audio, and comments below in news stories, with attribution to the scientist who made them.

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April 5, 2022


What is the most important take-home message you would like Americans to hear as this report is released?


James Gerber, Ph.D.

“The most important take-home message is that we are not on track to meet climate mitigation targets agreed to in the Paris climate accords of limiting warming to 1.5 degrees. However, there is some good news that goes along with that in the report, and one is that there is a lot of evidence that there are climate mitigation actions that we can take. In the energy sector, costs for solar and wind energy have come down 85% since 2010, and there’s been a lot of uptake of that—it’ll make huge improvements in the rate at which society is emitting greenhouse gases. And across all sectors, actually, there are many, many options that really are pretty cost-effective to further implement mitigation.” (Posted April 5, 2022 | Download Video)

James Gerber, Ph.D. (lead author, mitigation and development pathways in the near-to mid-term chapter)
Principal research scholar, Institute on the Environment, University of Minnesota

Paulina Jaramillo, Ph.D.

“We are not on track to limiting warming to 1.5 degrees Celsius, which is the goal of the Paris Agreement. Average annual greenhouse gas emissions during the last decade were the highest in human history. The good news is that there have been policies, laws, and activities that have enhanced energy efficiency, have reduced the rates of deforestation, and accelerated the deployment of renewable energy. We just need to increase the deployment of all of these mitigation options very rapidly in the next 10 years to be able to meet the 1.5 degree target.” (Posted April 5, 2022 | Download Video)

Paulina Jaramillo, Ph.D. (coordinating lead author, transport chapter)
Professor of engineering and public policy, Carnegie Mellon University

Jesse M. Keenan, Ph.D.

“I think one of the most important things that we can recognize is that, in our reduction of greenhouse gases, we still have a huge hill to climb. There are tremendous opportunities for us to reduce greenhouse emissions in fuel production, energy efficiency, the way we live our lives. But going into the future we are tremendously challenged, and we are certainly not on track with where we should be.” (Posted April 5, 2022 | Download Video)

Jesse M. Keenan, Ph.D. (review editor, buildings chapter)
Associate professor of real estate, School of Architecture, Tulane University

Gregory Nemet, Ph.D.

“The big message from the report is that the climate problem is getting worse, but the solutions are getting better. And the problem is getting worse because we’ve delayed action, and we haven’t actually reduced emissions, even though we see some progress in a few places. And the solutions getting better really comes across in looking at technologies like solar, like wind, like electric vehicles, where their costs have fallen by 85% in the case of solar and batteries, and their adoption has increased by orders of magnitude. And so the tools we have available are much better than we had ten years ago, when we had the data for the last IPCC report.” (Posted April 5, 2022 | Download Video)

Gregory Nemet, Ph.D. (lead author, emissions trends and drivers chapter)
Professor of public affairs, University of Wisconsin-Madison

Brent Sohngen, Ph.D

“The most exciting sort of take home message is that this is solvable. This problem, while it’s a big one, is actually solvable. And as a society, we’ve got options now, and we can do it. And that’s the main thing that this report has shown, is that by looking through the literature, we found that there are great ways to solve climate change. A couple that come to mind: One, what we could see in the solar and wind sectors is those costs have become really cheap. And in the area of research that I specifically do, which is to look at the agricultural and forestry sectors, those sectors, they haven’t become cheaper over time, but we now have a really good idea and a broader set of ideas for what we can do in those sectors to actually solve this problem. Everything from peat lands to reforesting old agricultural lands to avoiding deforestation in the Amazon, all of them are available to us and they’re not all that expensive.” (Posted April 5, 2022 | Download Video)

Brent Sohngen, Ph.D. (lead author, agriculture, forestry, and other land uses chapter)
Professor of environmental and resource economics, Ohio State University

Elke Weber, Ph.D.

“Even though the last 10 years have seen the highest increase in greenhouse gas emissions in human history, and we’re actually not on track to limit our warming to 1.5 degrees Celsius, the Working Group III report tells us that there are actions available to all sectors of our economy that can at least halve our emissions by 2030. And for the first time in IPCC history, the report has looked at what can be done by the general public, as consumers or as citizens, to reduce greenhouse gas emissions. Personal action by itself can only have a small impact, probably less than 5% of greenhouse gas emissions. But the report shows that changes in how we travel, eat, work, and live—when they are supported by the right infrastructure and technology—could reduce global greenhouse gas emissions by 40% to 70%.” (Posted April 5, 2022 | Download Video)

Elke Weber, Ph.D. (lead author, demand, services, and social aspects of mitigation chapter)
Gerhard R. Andlinger Professor for energy and the environment and professor of psychology and public affairs, Princeton University

What are the most significant opportunities for climate change mitigation in the U.S. related to land use?


James Gerber, Ph.D.

“The most significant opportunities for climate change mitigation in the U.S., I would say, are one: helping farmers to have support to farm sustainably. Reward farmers for farming in ways that increase soil carbon and also provide other environmental benefits. And another is for us to be very judicious about what we plant. And that can take on a few different forms. One is to really examine use of biofuels, in particular ethanol in the U.S. case, and really assess carefully if it’s meeting its intended environmental goals. And another is to really revisit our diets and consider what a more plant-based diet might look like.” (Posted April 5, 2022 | Download Video)

James Gerber, Ph.D. (lead author, mitigation and development pathways in the near-to mid-term chapter)
Principal research scholar, Institute on the Environment, University of Minnesota

What are the most significant opportunities for climate change mitigation in the U.S. related to transport?


Paulina Jaramillo, Ph.D.

“A combination of demand-side mitigation activities and low-carbon transport technologies are needed for mitigating emissions from the transport sector. Changes in urban form, the use of more public transport, less travel demand, those are demand-side mitigation. On the supply side for land-based transport, vehicle electrification powered with low-carbon electricity has the greatest potential for reducing emissions. In some other countries there may be other fuels like biofuels that play a role. For shipping and aviation, we need further investments in alternative low-carbon fuels like hydrogen and derivatives that can be used as drop-in fuels.” (Posted April 5, 2022 | Download Video)

Paulina Jaramillo, Ph.D. (coordinating lead author, transport chapter)
Professor of engineering and public policy, Carnegie Mellon University

What are the most significant opportunities for climate change mitigation in the U.S. related to buildings?


Jesse M. Keenan, Ph.D.

“The most important thing we can do in the United States is, in terms of reducing our carbon footprint in buildings, is to pass—at a building code level—more energy-efficient building codes. The more energy efficiency that we have, in terms of new and renovated buildings, the better off we are. It lowers our home costs. As consumers it’s cheaper for us. That’s a major advantage for the environment and for our household.

“The second thing we can do is simply consume less space. So going forward living in more modest units, not overconsuming jumbo housing units if you will, is good for us; it’s good for the environment.” (Posted April 5, 2022 | Download Video)

Jesse M. Keenan, Ph.D. (review editor, buildings chapter)
Associate professor of real estate, School of Architecture, Tulane University

What are the most significant greenhouse gas emissions trends and drivers in the U.S.?


Gregory Nemet, Ph.D.

“The most significant greenhouse gas emissions sources in the U.S. are the power sector, transportation sector, and industry. And we know from this assessment in the report that we have tools and strategies in each of those areas. So with the power sector, it’s a way of moving away from coal and gas to clean power sources like renewables. In transportation it’s moving away from gasoline and using electric vehicles that can be fueled by clean electricity. And in industry we have an array of tools including shifting to using hydrogen as an energy carrier and clean electricity throughout the industrial sector.” (Posted April 5, 2022 | Download Video)

Gregory Nemet, Ph.D. (lead author, emissions trends and drivers chapter)
Professor of public affairs, University of Wisconsin-Madison

What are the most significant opportunities for climate change mitigation in the U.S. related to agriculture and forestry?


Brent Sohngen, Ph.D.

“So in the U.S., because we have such a large amount of land and such a productive land base devoted to agriculture and forestry, we’ve got a huge number of options here. So in the agricultural sector, the opportunity to increase the number of acres that are devoted to conservation tillage, which is not tilling the landscape as intensively as we have in the past, that presents a big opportunity on millions—300 million, 400 million acres of cropland. We can also reduce emissions through mitigation of methane from cows and cow flatulation. We can also reduce nitrogen oxide emissions from some of the fertilizers we use on agricultural crops. So those would be big opportunities in the agricultural sector.

“Turning to forestry, this is the big sector in the U.S. because we have large potential in terms of increasing the management of our forest, and these forests can be managed both for a variety of ecosystem services, like biodiversity, ecosystem health, water quality, etc., etc., as well as timber products and carbon. All those things work together, actually, and can be improved and increased at the same time. At the same time we can add land to our forestry land base, by maybe 20 to 30 million acres and vastly increase the number of tons [of CO2] that we sequester in forests every year.” (Posted April 5, 2022 | Download Video)

Brent Sohngen, Ph.D. (lead author, agriculture, forestry, and other land uses chapter)
Professor of environmental and resource economics, Ohio State University

What are the most significant social aspects of mitigating climate change in the U.S., and what does that say about barriers to climate action?


Elke Weber, Ph.D.

“Barriers to climate action everywhere have to do with the fact that the climate crisis does not scare us—or most of us—in the same way that a foreign invasion, terrorism, or a medical pandemic do. This is, of course, not universally true, and especially young people around the world and in the United States are increasingly becoming anxious about the climate threat that is not being addressed. Resulting protest movements like Fridays for Future or the Sunrise Movement have some potential to alert other segments of society to the urgency of the crisis. Barriers to climate action in wealthy countries like the U.S. also have to do with our reluctance to trade in our unsustainable lifestyles for some other ways of living that are much less well known and will require some adjustments or sacrifices compared to our current ways of living.” (Posted April 5, 2022 | Download Video)

Elke Weber, Ph.D. (lead author, demand, services, and social aspects of mitigation chapter)
Gerhard R. Andlinger Professor for energy and the environment and professor of psychology and public affairs, Princeton University

Creative Commons LicenseThe text and video on this page are licensed as Creative Commons CC BY-SA 4.0. Journalists are free to use any text or video on this page with or without attribution to SciLine.

James Gerber, Ph.D., Principal research scholar, Institute on the Environment, University of Minnesota

None.

Paulina Jaramillo, Ph.D., professor of engineering and public policy, Carnegie Mellon University

None.

Jesse M. Keenan, Ph.D., associate professor of real estate, School of Architecture, Tulane University

I have no conflicts to declare as it relates to IPCC work. I am an advisor and shareholder at Jupiter Intelligence, ClimateCheck and Forerunner, which are all climate intelligence firms. I also conduct research for the federal government, including the U.S. General Services Administration and the U.S. Army Corps of Engineers. However, my commentary is solely my opinion and not associated with any of these entities or affiliations. But, none of these activities relate to the IPCC work herein.

Gregory Nemet, Ph.D., professor of public affairs, University of Wisconsin-Madison

None.

Brent Sohngen, Ph.D., professor of environmental and resource economics, Ohio State University

None stated.

Elke Weber, Ph.D., Gerhard R. Andlinger Professor for energy and the environment and professor of psychology and public affairs, Princeton University

Dr. Weber conducts research on psychological and social determinants of climate action and is supported by the National Science Foundation. She is on the board of Rare, a conservation NGO.