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Carryover Cooking: Part of the Challenge of Meeting the Paris Agreement

Tuesday, August 8th, 2017

This entry was originally published on The Conversation. It is an update of an article originally published in December 2014. The point of the article is that the heat already stored, primarily in the oceans, will continue to cause the surface air temperature to rise for some time. It’s like taking a large roast out of the oven. The temperature in the middle of the roast will continue to rise for a while. (Carryover Cooking)

Since the 2015 Paris Agreement to limit warming of the average surface air temperature to 2.0 degrees C, with a stated ambition to limit warming to 1.5 degrees C, there has been a lot of research of what is needed to make the Paris goals possible. (For example, What would it take to achieve the Paris temperature targets?).

What is clear is that meeting the goals of Paris is tough. It is social engineering and geoengineering at a level that is, to me, incomprehensible. We will, ultimately, have to learn to take carbon dioxide out of the atmosphere – as well as to adapt.

The scenarios that allow us to meet Paris goals are complex.They are a combination of complexity, uncertainty, and unlikelihood that they are a communication nightmare. They help us think about things, but they do not prescribe how to address climate change.

Here is the original article from The Conversation.

File 20170703 17450 gkktjh
Best-case scenario, how much are we locked into?

If we stopped emitting greenhouse gases right now, would we stop climate change?

Richard B. Rood, University of Michigan

Earth’s climate is changing rapidly. We know this from billions of observations, documented in thousands of journal papers and texts and summarized every few years by the United Nations’ Intergovernmental Panel on Climate Change. The primary cause of that change is the release of carbon dioxide from burning coal, oil and natural gas.

One of the goals of the international Paris Agreement on climate change is to limit the increase of the global surface average air temperature to 2 degrees Celsius, compared to preindustrial times. There is a further commitment to strive to limit the increase to 1.5℃.

Earth has already, essentially, reached the 1℃ threshold. Despite the avoidance of millions of tons of carbon dioxide emissions through use of renewable energy, increased efficiency and conservation efforts, the rate of increase of carbon dioxide in the atmosphere remains high.

International plans on how to deal with climate change are painstakingly difficult to cobble together and take decades to work out. Most climate scientists and negotiators were dismayed by President Trump’s announcement that the U.S. will withdraw from the Paris Agreement.

But setting aside the politics, how much warming are we already locked into? If we stop emitting greenhouse gases right now, why would the temperature continue to rise?

Basics of carbon and climate

The carbon dioxide that accumulates in the atmosphere insulates the surface of the Earth. It’s like a warming blanket that holds in heat. This energy increases the average temperature of the Earth’s surface, heats the oceans and melts polar ice. As consequences, sea level rises and weather changes.

Global average temperature has increased. Anomalies are relative to the mean temperature of 1961-1990. Based on IPCC Assessment Report 5, Working Group 1.
Finnish Meteorological Institute, the Finnish Ministry of the Environment, and, CC BY-ND

Since 1880, after carbon dioxide emissions took off with the Industrial Revolution, the average global temperature has increased. With the help of internal variations associated with the El Niño weather pattern, we’ve already experienced months more than 1.5℃ above the average. Sustained temperatures beyond the 1℃ threshold are imminent. Each of the last three decades has been warmer than the preceding decade, as well as warmer than the entire previous century.

The North and South poles are warming much faster than the average global temperature. Ice sheets in both the Arctic and Antarctic are melting. Ice in the Arctic Ocean is melting and the permafrost is thawing. In 2017, there’s been a stunning decrease in Antarctic sea ice, reminiscent of the 2007 decrease in the Arctic.

Ecosystems on both land and in the sea are changing. The observed changes are coherent and consistent with our theoretical understanding of the Earth’s energy balance and simulations from models that are used to understand past variability and to help us think about the future.

A massive iceberg – estimated to be 21 miles by 12 miles in size – breaks off from Antarctica’s Pine Island Glacier.

Slam on the climate brakes

What would happen to the climate if we were to stop emitting carbon dioxide today, right now? Would we return to the climate of our elders?

The simple answer is no. Once we release the carbon dioxide stored in the fossil fuels we burn, it accumulates in and moves among the atmosphere, the oceans, the land and the plants and animals of the biosphere. The released carbon dioxide will remain in the atmosphere for thousands of years. Only after many millennia will it return to rocks, for example, through the formation of calcium carbonate – limestone – as marine organisms’ shells settle to the bottom of the ocean. But on time spans relevant to humans, once released the carbon dioxide is in our environment essentially forever. It does not go away, unless we, ourselves, remove it.

In order to stop the accumulation of heat, we would have to eliminate not just carbon dioxide emissions, but all greenhouse gases, such as methane and nitrous oxide. We’d also need to reverse deforestation and other land uses that affect the Earth’s energy balance (the difference between incoming energy from the sun and what’s returned to space). We would have to radically change our agriculture. If we did this, it would eliminate additional planetary warming, and limit the rise of air temperature. Such a cessation of warming is not possible.

So if we stop emitting carbon dioxide from burning fossil fuels today, it’s not the end of the story for global warming. There’s a delay in air-temperature increase as the atmosphere catches up with all the heat that the Earth has accumulated. After maybe 40 more years, scientists hypothesize the climate will stabilize at a temperature higher than what was normal for previous generations.

This decades-long lag between cause and effect is due to the long time it takes to heat the ocean’s huge mass. The energy that is held in the Earth by increased carbon dioxide does more than heat the air. It melts ice; it heats the ocean. Compared to air, it’s harder to raise the temperature of water; it takes time – decades. However, once the ocean temperature is elevated, it will release heat back to the air, and be measured as surface heating.

Scientists run thought experiments to help think through the complex processes of emissions reductions and limits to warming. One experiment held forcing, or the effect of greenhouse gases on the Earth’s energy balance, to year 2000 levels, which implies a very low rate of continued emissions. It found as the oceans’ heating catches up with the atmosphere, the Earth’s temperature would rise about another 0.6℃. Scientists refer to this as committed warming. Ice, also responding to increasing heat in the ocean, will continue to melt. There’s already convincing evidence that significant glaciers in the West Antarctic ice sheets are lost. Ice, water and air – the extra heat held on the Earth by carbon dioxide affects them all. That which has melted will stay melted – and more will melt.

Ecosystems are altered by natural and human-made occurrences. As they recover, it will be in a different climate from that in which they evolved. The climate in which they recover will not be stable; it will be continuing to warm. There will be no new normal, only more change.

Runaway glaciers in Antarctica.

Best of the worst-case scenarios

In any event, it’s not possible to stop emitting carbon dioxide right now. Despite significant advances in renewable energy sources, total demand for energy accelerates and carbon dioxide emissions increase. As a professor of climate and space sciences, I teach my students they need to plan for a world 4℃ warmer. A 2011 report from the International Energy Agency states that if we don’t get off our current path, then we’re looking at an Earth 6℃ warmer. Even now after the Paris Agreement, the trajectory is essentially the same. It’s hard to say we’re on a new path until we see a peak and then a downturn in carbon emissions. With the approximately 1℃ of warming we’ve already seen, the observed changes are already disturbing.

There are many reasons we need to eliminate our carbon dioxide emissions. The climate is changing rapidly; if that pace is slowed, the affairs of nature and human beings can adapt more readily. The total amount of change, including sea-level rise, can be limited. The further we get away from the climate that we’ve known, the more unreliable the guidance from our models and the less likely we will be able to prepare.

It’s possible that even as emissions decrease, the carbon dioxide in the atmosphere will continue to increase. The warmer the planet gets, the less carbon dioxide the ocean can absorb. Rising temperatures in the polar regions make it more likely that carbon dioxide and methane, another greenhouse gas that warms the planet, will be released from storage in the frozen land and ocean reservoirs, adding to the problem.

If we stop our emissions today, we won’t go back to the past. The Earth will warm. And since the response to warming is more warming through feedbacks associated with melting ice and increased atmospheric water vapor, our job becomes one of limiting the warming. If greenhouse gas emissions are eliminated quickly enough, within a small number of decades, it will keep the warming manageable and the Paris Agreement goals could be met. It will slow the change – and allow us to adapt. Rather than trying to recover the past, we need to be thinking about best possible futures.

This article was updated on July 7, 2017 to clarify the potential effects from stopping carbon dioxide emissions as well as other factors that affect global warming.

The ConversationThis article has been updated from an original version published in December 2014, when international climate talks in Lima were laying the foundation for the 2015 Paris Agreement.

Richard B. Rood, Professor of Climate and Space Sciences and Engineering, University of Michigan

This article was originally published on The Conversation. Read the original article.

Fear and Loathing, Irony and Deception

Saturday, January 14th, 2017

Fear and Loathing, Irony and Deception

Several colleagues have told me that my last blog / editorial was a struggle to find optimism. After finishing that blog, I had no sense of optimism. (I expect an updated version of the editorial will be published in the February print edition of EOS.)

During the presidential transition, a number of statements hostile to climate science and climate scientists have risen and, perhaps, fallen. There was the request for names of climate scientists in the Department of Energy. There were the statements about NASA’s Earth observations being cut or eliminated – some sort of merger with NOAA, the National Oceanographic and Atmospheric Administration. There is the ongoing anxiety, in some cases panic, about the collection, management, and provision of climate data by the U.S. government. There are the many concerns about the future of the Environmental Protection Agency. (more…)

The whole silly warming pause, warming hiatus thing

Saturday, March 1st, 2014

This is a synthesis of the knowledge we have about the pause or hiatus in warming. In my little collection of blogs, I have written about this several times, and I link some of those entries below. Sometime in 2005, those in the lobby opposing climate-change science started to beat the drum that warming of the planet had stopped and that the assessments of the Intergovernmental Panel on Climate Change (IPCC) were in fundamental error. The drumbeat was amplified by a knowledge-twisting article in the Daily Mail, which I discussed in It’s Not Getting Warmer – Again, Really? Increased credibility to the pause in warming was added by an article in The Economist reporting on the story of the “pause” and that, indeed, if you looked at the temperature record it was not documenting an unrelenting increase in global-average surface temperature (from when the Economist article was published).

When I first wrote about the warming pause, I referred to my piece Form of Argument on how to analyze this news report. The article focused on a single piece of information, isolated, and posed as an unanswerable contradiction. The reporting and figures did not carry the full descriptions of the graphs that proved no warming. There were also implications of stealth. The list goes on. The warming hiatus as a challenge to the body of science-based knowledge on climate change was a manufactured problem.


Science, Belief and the Volcano:

Sunday, March 8th, 2009

Science, Belief and the Volcano:

In January 2008 there was an article in the National Geographic called the The Gods Must Be Restless. The author, Andrew Marshall, describes Mbah Marijan, who has the job of satisfying the ogre that inhabits the volcano Merapi in Indonesia. The volcano is about to explode, the government has ordered an evacuation and Marijan is not convinced. Quoting the article:

“The alerts are merely guesses by men at far remove from the spirit of the volcano. The lava dome collapse? ‘That’s what the experts say,’ he (Marijan) says, smiling. ‘But an idiot like me can’t see any change from yesterday.’ ” (more…)

Designing Post-2012 International Climate Change Policy

Friday, December 7th, 2007

The 2007 UN-sponsored climate change negotiations opened in Bali, Indonesia this week. By the end of the conference on December 14, the world community may agree to a two-year “roadmap,” as called for by the UN Secretary-General, for negotiating an agreement to guide climate change mitigation efforts after the end of the Kyoto Protocol’s 2008-2012 commitment period. A number of academics, analysts, nongovernmental organizations and related processes have proposed various ways of moving forward with international climate change policy, including the Pew Center on Global Climate Change’s Dialogue at Pocantico, the UN Foundation and the Club of Madrid’s Global Leadership for Climate Action, and the Centre for Global Studies’ L20 concept of engaging the most important developed and developing countries on this issue, which is similar to the Bush Administration’s Big Economies process. (more…)


Tuesday, May 8th, 2007

Summer reading opportunities abound for anyone interested climate change. The IPCC’s Fourth Assessment Report includes recently released contributions from Working Group I on the science of climate change (with a Summary for Policy Makers, Technical Summary, and individual chapters now available), from Working Group II on impacts, adaptation, and vulnerability (WG-II SPM), and from Working Group III on climate change mitigation (WG-III SPM).

For anyone looking for an engaging overview of climate change, I’d strongly recommend The Science and Politics of Global Climate Change: A Guide to the Debate (Cambridge University Press, 2006) by Andrew Dessler and Edward Parson. I recently reviewed the book for BAMS (you can download my review here) and found it to be one of the most readable overviews that I’ve seen.