Study: Coal-Fired Power Plants Emit Pollutants That Keep the Earth Cool
Last week a new study reported that replacing coal with natural gas might actually worsen climate change in the short term. The study was done by Tom Wigley, who is a senior research associate at the National Center for Atmospheric Research (NCAR). The title of the study is Coal to gas: The influence of methane leakage and will be published in next month’s Climatic Change Letters.
What the study projects is that the amount of methane leaking from gas wells will influence the future temperature rise from climate change: The higher the methane leakage, the higher the future temperature. This is shown by the following graph from the report:
Temperature Increase as a Function of Methane Leakage
Since there is always some methane leakage, and because methane is a very strong greenhouse gas, it was widely reported that the predicted poor showing of natural gas in the short term was due to the gas leakage. More importantly, the widely-reported message relayed by the media is that this study shows that natural gas can’t do much to mitigate climate change.
Ah, but there is a catch that hasn’t gotten much attention (and has been in some cases purposely suppressed).
Notice that the projected temperature increases in every case — even when there is no methane leakage. That indicates that something else is going on here, which is explained in the following story
Advocates for natural gas drilling have trumpeted its environmental benefits as an alternative to the coal that produces most of America’s electricity, noting that natural gas emits about half the amount of carbon dioxide when burned as coal does.
But a new study sheds doubt on that claim, finding that a shift from coal to natural gas would in fact accelerate the planet’s rising temperatures before slightly reducing them. Tom Wigley of the National Center on Atmospheric Research found that swapping the two fuels would increase global temperatures over the next four decades by about a tenth of a degree.
Wigley’s study does not dispute the fact that natural gas produces far less carbon dioxide, a key culprit in pushing temperatures steadily upwards. But coal also gives off sulfates and other particles that dissipate more quickly than coal fumes and effectively reflect sunlight away from the earth, cooling rather than warming. Those particles do increase air pollution and the likelihood of acid rain, but from a global warming perspective they are a source of relief.
Did you follow that? Coal has higher particulate emissions that increase air pollution, but they help reflect the sun away from the earth. Thus, cities like Linfen, China, pictured below, are sitting in the catbird seat as far as global warming goes. As you can see, no global warming concerns for them as the particulate emissions are quite effectively preventing sunlight from reaching the surface:
Pollution from Coal Emissions in Linfen, China. (Photo Source).
So as Linfen, China switches to natural gas (which they have in fact been doing), it will simply speed up global warming. Now I suspect you are beginning to see that this story may be more complex than the refutation of natural gas that the media headlines have indicated.
Since the graphic shows that even zero leakage of methane caused the projected temperature to rise, I was curious as to just how much of the effect was due to the emissions of the coal plants themselves. So I contacted Tom Wigley, the author of the paper, and posed the following question: “Is it true per your models that if we switched from coal to a zero emissions source of electricity that the short-term climate change impact would also be negative due to the loss of the cooling effect from coal’s particulate emissions?”
He replied to my e-mail fairly quickly: “Yes. This “problem” was first pointed out by me in 1991. I’ll attach this paper, plus the coal-to-gas paper. In 1991 I did not consider carbonaceous aerosols. The issue of balancing the disbenefit of less aerosols implies warming vs the benefit of less SO2 emissions implies pollution benefits is a tricky one.” (The 1991 paper he referred to was “Could Reducing Fossil-Fuel Emissions Cause Global Warming?” — published in Nature).
So there you have it. Per this study, shutting down all coal-fired power plants and not even replacing them would cause the temperature to increase in the short term because of the loss of sunlight-reflecting pollutants. Thus, the real story here is about the secondary effect of coal-fired power plants and not about any deficiencies of natural gas.
Media Distorts the Facts by Playing With Headlines
But how did the media report on the story?
From the Washington Post: Study: Replacing coal with natural gas would do little for climate change
From the L.A. Times: Clean natural gas? Not so fast, study says
From Time: Natural Gas Can Save the Climate? Not Exactly
From USA Today: Study: Climate change little affected by shift from coal to natural gas
From the Charleston Gazette: More questions about climate benefits of gas switch
From the International Business Times: Natural Gas cannot Solve Earth’s Climate Woes: Study?
From Mother Jones: Natural Gas: Not That Great After All
From Joe Romm at Climate Progress: Natural Gas Bombshell: Switching From Coal to Gas Increases Warming for Decades, Has Minimal Benefit Even in 2100
What is the takeaway message from all of these headlines? Clearly it is that the benefits of natural gas are overrated. But the media broadly got this one wrong by pointing fingers at natural gas instead of noting the peculiarity of the temperature increase even with zero methane leakage. Had they done that, they would have realized that the short term impact here is from closing down the coal plants and not due to what replaces them.
In fact, they could replace “natural gas” with “solar power” or “wind power” in every one of those headlines above and it would still be consistent with the paper. Thus, those headlines could have read:
Study: Replacing coal with solar power would do little for climate change
More questions about climate benefits of wind power switch
Solar Power: Not That Great After All
Or they could have just as easily gone with:
The Solution to Global Warming is More Coal-Fired Power Plants
Linfen, China Leads Fight Against Global Warming
And while those are consistent with the paper being reported upon, they convey an entirely different message than the one the media did convey. The media gets an “F” on reporting this story in the way that they did.
Note: Incidentally, I attempted to point this out on some of the sites pushing this story as a refutation of natural gas as a bridge fuel (including some of the stories that I linked to above). Many of those stories were running with the theme “See, we have to go straight to solar or wind power.” Some of those sites chose not to publish my comments, even though mine were quite civil — and they freely published comments that agreed with their story. So it is clear that some of them have an agenda, and that they aren’t going to let facts get in the way of that agenda. When they resort to censorship to push a false narrative, they have lost all integrity in my eyes. They are not only lemmings, they are dishonest lemmings.
By. Robert Rapier
Source: R Squared Energy Blog