Climate Change
Hypothetical

CLIMATE CHANGE ... If We Dig Out All Our Fossil Fuels, Here’s How Hot We Can Expect It to Get

Burgess COMMENTARY

Peter Burgess

CLIMATE CHANGE ... If We Dig Out All Our Fossil Fuels, Here’s How Hot We Can Expect It to Get

World leaders are once again racing to avert disastrous levels of global warming through limits on greenhouse gas emissions. An agreement may be in reach, but because of the vast supplies of inexpensive fossil fuels, protecting the world from climate change requires the even more difficult task of disrupting today’s energy markets.

The White House last month released a blueprint to reduce United States emissions by as much as 28 percent by 2025. The plan lays the groundwork for the formal international climate talks this December in Paris, where the goal is a treaty on emissions that will seek to limit the rise in global temperatures to 3.6 degrees Fahrenheit above preindustrial levels. Beyond 3.6 degrees, scientists say, the most catastrophic climate consequences will occur, possibly including the melting of the Greenland ice sheet.

Forging a treaty in Paris would be no small task, yet would be just the beginning of a solution. The greater challenge will be deciding how much of the world’s abundant supply of fossil fuels we simply let lie. (Bill McKibben and more recently The Guardian have taken a maximal position in their Leave It in the Ground campaign.)

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A huge excavator shoveled earth and brown coal near the Boehlen-Lippendorf power station in Germany in 2013. Credit Michaela Rehle/Reuters

To understand the scope of this challenge, I’ve tallied the projected warming from fossil fuels extracted so far and the projected warming capacity of various fossil fuels that can be extracted with today’s technology. This accounting was done by taking the embedded carbon dioxide in each energy source and using a standard model for the relationship between cumulative carbon emissions and long-run temperature changes based on a 2009 Nature article. (More detail on the method is available here.)

For those who don’t like suspense, here’s the total: an astonishing 16.2 degrees. And here’s how that breaks down. Since the industrial revolution, fossil fuels have warmed the planet by about 1.7 degrees. We are already experiencing the consequences of this warming. In recent weeks, we have learned that the world had its warmest winter on record and that Arctic sea ice hit a new low, even as intense storms continue to inflict harm on communities globally.

Next, look at fossil fuel reserves, the deposits we know to be recoverable under today’s prices and technology. That is, they are inexpensive to access. If we were to use all of this coal, natural gas and petroleum, the planet would warm by an additional 2.8 degrees. Add the heat from those reserves to the 1.7 degrees from what has already been emitted, and you get a world that is 4.5 degrees warmer since the industrial revolution; this is beyond scientists’ recommended 3.6-degree threshold.

The next set of fossil fuels in line is referred to as resources, rather than reserves. The difference is that they are recoverable with today’s technology, but not at current prices. There is 3.1 degrees’ worth of warming if the oil and natural gas in this category are utilized, which would lead to a total increase in global temperatures of 7.6 degrees.

Continue reading the main storyContinue reading the main storyContinue reading the main story This warming does not even consider our coal resources. A middle-of-the-road estimate of the coal that qualifies as resources indicates that its use would lead to an additional increase of 8.6 degrees. Thus, the use of all reserves and resources would lead to a total increase of 16.2 degrees. Today’s climate and planet would very likely be unrecognizable.

Buried Fuel and a Much Warmer World

Scientists predict global disaster at 3.6 degrees Fahrenheit over pre-industrial temperatures; there is enough fossil fuel extracted and within reach to raise temperatures 16.2 degrees. Associated warming in degrees Fahrenheit 8.6 3.1 2.8 1.7° Coal resources (accessible with current technology but not profitable at current prices) Oil and gas resources (accessible with current technology but not profitable at current prices) Fossil fuel reserves (profitable to access with current technology) Fossil fuel already emitted Source: Calculations use the “carbon-climate response” model from Matthews et al. (2009, Nature) to convert cumulative carbon emissions into global mean temperature changes. Without pricing carbon to reflect expected climate damages, all of this coal, oil and natural gas is worth many trillions of dollars, so keeping it in the ground would mean passing up economic opportunities that are waiting to be taken and turning our backs on a long history of going to great lengths to recover these energy sources. A January study in Nature developed estimates of which fuels would have to be abandoned to stay below the 3.6-degree threshold. It found that most Canadian tar sands; all Arctic oil and gas; and a significant share of potential shale gas would need to stay locked up. It also found that major coal producers like the United States would need to keep 90 percent of their reserves in the ground.

There are essentially only three long-run solutions to the climate challenge. The first is to price carbon emissions to reflect the damages from climate change. In practice, this means pricing carbon in as many parts of the world as possible — and ideally, globally — so that there is a level playing field for all energy sources. There has been important progress in this area, including in the European Union, individual American states and regions (for example, California and the Northeast’s Regional Greenhouse Gas Initiative), and parts of China.

And there are several ways to introduce carbon pricing, as a New York Times Op-Ed by David Hayes and James Stock underscored. But we are a long way from a global price on carbon, and the prices in existing carbon markets are lower than the projected damages from increased carbon emissions.

The second way to disrupt the energy market is to have low-carbon energy sources like nuclear, wind and solar become cheaper than their fossil fuel competition. Although there has been much progress in reducing the costs of wind and solar recently, they generally remain more expensive than fossil fuels. Further, the fracking revolution makes it clear that there will be continued technical advances that reduce the costs of recovering fossil fuels.

Indeed, it is well known that there are ample supplies of coal deeper beneath the Earth’s surface that do not yet qualify as resources, and there is increasing evidence that energy from methane hydrates may become relevant commercially. In other words, it seems unlikely that today’s low carbon energy sources will play a major role in the solution without significant public investment in research, development and test deployments of new technologies.

The third approach is to continue using those fuels, but capture and store the carbon before it is released or pull it out of the atmosphere after its release. Neither approach has yet been proved to work at scale, and costs remain high. Even if costs come down, it will very likely remain more expensive than using fossil fuels without capture and storage, so a carbon price would be necessary for it to be applied broadly. A related idea is to reflect sunlight away from the earth so temperatures do not rise as much. This approach does not reduce the buildup of carbon dioxide in the atmosphere, and there is agreement that further research is necessary.

If we use all of the fossil fuels in the ground, the planet will warm in a way that is difficult to imagine. Unless the economics of energy markets change, we are poised to use them.

Michael Greenstone, the Milton Friedman professor of economics at the University of Chicago, runs the Energy Policy Institute there. He was the chief economist of President Obama’s Council of Economic Advisers from 2009 to 2010. The Upshot provides news, analysis and graphics about politics, policy and everyday life. Follow us on Facebook and Twitter. Sign up for our weekly newsletter.

Continue reading the main story RECENT COMMENTS elmst 14 days ago This article is fundamentally flawed, it assumes a linear relationship between greenhouse gas emissions and temperature, which s not the... Dr. John 14 days ago With the growing population of the world needing to be fed, the slowly riding temperatures expand both the amount of arable land and the... Keith Lewis 14 days ago Disclaimer: This article does not account for fossil fuel resources that are not available with current technologies.Therefore, 16.2 degrees... SEE ALL COMMENTS

http://www.nature.com/nature/journal/v459/n7248/abs/nature08047.html

The proportionality of global warming to cumulative carbon emissions

See associated Correspondence: Matthews, Nature 514, 434 (October 2014)

H. Damon Matthews1, Nathan P. Gillett2, Peter A. Stott3 & Kirsten Zickfeld2

H. Damon Matthews ...Department of Geography, Planning and Environment, Concordia University, 1455 de Maisonneuve Blvd W., Montreal, Quebec, H3G 1M8, Canada

Nathan P. Gillett and Kirsten Zickfeld ... Canadian Centre for Climate Modelling and Analysis, Environment Canada, 3800 Finnerty Road, Victoria, British Columbia, V8P 5C2, Canada

Peter A. Stott ...Met Office Hadley Centre, FitzRoy Road, Exeter, Devon, EX1 3PB, UK

Correspondence to: H. Damon Matthews1 Correspondence and requests for materials should be addressed to H.D.M. (Email: dmatthew@alcor.concordia.ca).

The global temperature response to increasing atmospheric CO2 is often quantified by metrics such as equilibrium climate sensitivity and transient climate response1. These approaches, however, do not account for carbon cycle feedbacks and therefore do not fully represent the net response of the Earth system to anthropogenic CO2 emissions. Climate–carbon modelling experiments have shown that: (1) the warming per unit CO2 emitted does not depend on the background CO2 concentration2; (2) the total allowable emissions for climate stabilization do not depend on the timing of those emissions3, 4, 5; and (3) the temperature response to a pulse of CO2 is approximately constant on timescales of decades to centuries3, 6, 7, 8. Here we generalize these results and show that the carbon–climate response (CCR), defined as the ratio of temperature change to cumulative carbon emissions, is approximately independent of both the atmospheric CO2 concentration and its rate of change on these timescales. From observational constraints, we estimate CCR to be in the range 1.0–2.1 °C per trillion tonnes of carbon (Tt C) emitted (5th to 95th percentiles), consistent with twenty-first-century CCR values simulated by climate–carbon models. Uncertainty in land-use CO2 emissions and aerosol forcing, however, means that higher observationally constrained values cannot be excluded. The CCR, when evaluated from climate–carbon models under idealized conditions, represents a simple yet robust metric for comparing models, which aggregates both climate feedbacks and carbon cycle feedbacks. CCR is also likely to be a useful concept for climate change mitigation and policy; by combining the uncertainties associated with climate sensitivity, carbon sinks and climate–carbon feedbacks into a single quantity, the CCR allows CO2-induced global mean temperature change to be inferred directly from cumulative carbon emissions.