Global Warming: Can World's Nations Agree on 2 Degrees?

Stanford experts weigh in on Paris climate talks

Leaders from around the world will soon gather in Paris for a highly anticipated United Nations conference on climate change. Unlike previous talks, the 21st gathering of the “Conference of the Parties” to the U.N. Framework Convention on Climate Change is widely believed to hold potential for major progress toward reducing greenhouse gas emissions. This, in turn, could prevent the world from passing a scientifically recognized point of no return for catastrophic warming.

Although the world’s biggest emitters, including China and the U.S., have already pledged significant emissions reductions, most scientists agree that these commitments are not enough to avoid a dangerous threshold - 2 degrees Celsius above pre-industrial levels. In Paris, negotiators will discuss how to make up the difference - by involving local governments and businesses, for example - and how to fund clean technology and climate change adaptation in poor countries.

Stanford scholars have pioneered the research needed to recognize and meet the challenge of climate change since the issue came to light more than 20 years ago. Their findings, many of which are recorded in reports of the U.N.’s Intergovernmental Panel on Climate Change, help inform delegates from 195 countries who are slated to gather in Paris. Here, Stanford experts on climate change-related issues ranging from energy and ecosystems to law and economics share their perspectives on the upcoming talks.

Q&A: Can World’s Nations Agree on 2 Degrees?

Why are the upcoming Paris climate talks different from the past 20 COPs? Is there greater momentum for an agreement now?

Noah Diffenbaugh

Associate Professor, School of Earth, Energy & Environmental Sciences and Senior Fellow at the Woods Institute for the Environment

“I’m not aware of a situation where we’ve had so many countries on the record with so many self-identified commitments. Stabilizing emissions at any level requires taking the emissions trajectory in the other direction. These commitments represent a real new step in that direction.”

David Hayes

Distinguished Visiting Lecturer at Stanford Law School, Visiting Senior Fellow at Center for American Progress and Consulting Professor at Stanford Woods Institute for the Environment

“The Paris COP represents a particularly important inflection point for the international community’s approach to climate change. If successful, it will launch a new architecture that focuses on country-specific commitments to reduce greenhouse gas emissions, introducing more accountability and realism into the process. China’s commitment is particularly important because it makes it more difficult for developing nations to remain in the shadows. The U.S. is making a substantial commitment and, perhaps as importantly, President Obama is speaking out forcefully on the imperative that the U.S. and the international community move in tandem to take on climate change.”

What are the economic implications of a binding agreement?

Marshall Burke

Assistant Professor, School of Earth, Energy & Environmental Sciences and Center Fellow at Freeman Spogli Institute for International Studies and, by courtesy, at Stanford Woods Institute for the Environment

“The economic implications depend heavily on what targets are specified in the agreement. Our research shows that, relative to a business-as-usual world that warms 4 degrees Celsius by 2100, keeping the increase to 2 degrees Celsius roughly halves the economic damage from climate change. And you’d be halving a very big number: Our research estimates that losses under 4-degree Celsius warming could be as large as 20 to 25 percent of global GDP.”

Before the Paris talks, countries must submit pledges (“INDC Plans”) to reflect their commitments for reducing GHG emissions after 2020. Are they realistic?

Charles Kolstad

Senior Fellow at Stanford Institute for Economic Policy Research and Precourt Institute for Energy; Professor, by courtesy, of Economics

“I think the INDCs are a very realistic way to take first steps towards global action. It is true that the sum of obligations embodied in the submitted INDCs is not all that spectacular. But it is still action - and that is important. Next year, at COP 22, we can work to tighten the INDCs further.”

Jim Leape

Cox Consulting Professor in School of Earth, Energy & Environmental Sciences; and Consulting Professor at Stanford Woods Institute for the Environment

“The nature of the INDC process is that countries’ commitments are voluntary, or “nationally determined,” and so they are quite consistently “realistic” in the sense that countries should be able to deliver on them. These goals are realistic in terms of achievability, but they leave a lot of work to be done. A prime example is the fires that have been burning in Indonesia for the past three months have released more greenhouse gases than the total annual emissions of Japan, Germany or, soon, Russia. On most days in September and October, the emissions from the fires exceeded the daily emissions of the U.S. So, action on forests and agriculture is a crucial piece of the puzzle.”

Rob Jackson

Michelle and Kevin Douglas Provostial Professor in School of Earth, Energy & Environmental Sciences; and Senior Fellow at Stanford Woods Institute for the Environment and Precourt Institute for Energy

“I doubt that the Paris meeting will limit warming to 2 degrees Celsius. Based on what countries have committed so far, the Earth would likely warm at least 3 degrees Celsius this century. What Paris could do is establish a flexible baseline that allows countries to strengthen their commitments later. Only then might we keep warming below 2 degrees and avoid the most expensive and damaging outcomes.”

What are the costs and benefits to society by taking action on climate change sooner rather than later?

Charles Kolstad

Senior Fellow at Stanford Institute for Economic Policy Research and Precourt Institute for Energy; Professor, by courtesy, of Economics

“Action today need not be enormously costly. The steps President Obama has ordered - a clean power plan and fuel efficiency standards for cars - are modest but a great start for the U.S. In the end, it will be cheaper than having to take even more drastic action if we were to do nothing for another decade or two.”

Elizabeth Hadly

Paul S. and Billie Achilles Professor in Environmental Biology and Senior Fellow at the Stanford Woods Institute for the Environment

“The sooner we do it - mitigation and adaptation - the more control we have over the outcome when it comes to impacts such as sea level rise, which threatens millions of people in the U.S. alone. An agreement also means good things for collective international action. The fact that you can get so many leaders together to acknowledge climate change’s impacts and act on them, it means they're going to be called to task going forward.”

How might we overcome some of the barriers that could hinder compliance with the terms of the expected agreement, in both the U.S. and other top-emitting countries?

David Hayes

Distinguished Visiting Lecturer at Stanford Law School, Visiting Senior Fellow at Center for American Progress and Consulting Professor at Stanford Woods Institute for the Environment

“Domestic resistance to greenhouse gas reduction commitments within leading nations - including the U.S. - could significantly undercut effectiveness of the agreement. In my view, one way to reduce this resistance is to focus on the positive benefits of moving toward a clean energy economy, including job creation, investment in needed infrastructure, and opportunities to apply U.S. innovation and technology to one of society’s most fundamental needs: energy.”

Michael Wara

Associate Professor of Law

“For the U.S., the key issues are legal risks for the various new regulations and the overarching political risk; a Republican in the White House probably means no compliance. For the E.U., the risks are macroeconomic and political and have to do with the strength of the E.U. and the European community as a center of environmental policymaking for member countries. For China, the risks are very hard to evaluate. China’s main compliance mechanism for its INDC – the one that will really deliver reductions – is rebalancing its economy. Whether or not China’s president Xi Jinping can pull this off while avoiding a hard landing is impossible to say right now, but I must say that the last six months have made me relatively less optimistic about this outcome. If China stumbles in its economic transformation, it may well revert to its earlier, investment-heavy approach to economic development - which would cause it to blow through its target.”