[Sustain] New Science: Zero Emissions Necessary To Avert Climate Disasters

[Eric Brooks]

Hi all,

Here is an article that gets to the heart of the climate crisis. These 
new findings actually make our jobs much easier, because they allow us 
to start saying to people and policy makers that global civilisation 
must become a zero carbon emitter as soon as possible. No more need to 
haggle about CO2 parts per million, or percentages of reduction by this 
date or that one. We can just start saying to people that we need to 
become a zero carbon emitting civilisation as immediately as we can.

Here is the article:

http://www.washingtonpost.com/wp-dyn/content/article/2008/03/09/AR2008030901867_pf.html

*Carbon Output Must Near Zero To Avert Danger, New Studies Say*

By Juliet Eilperin
Washington Post Staff Writer
Monday, March 10, 2008; A01

The task of cutting greenhouse gas emissions enough to avert a dangerous 
rise in global temperatures may be far more difficult than previous 
research suggested, say scientists who have just published studies 
indicating that it would require the world to cease carbon emissions 
altogether within a matter of decades.

Their findings, published in separate journals over the past few weeks, 
suggest that both industrialized and developing nations must wean 
themselves off fossil fuels by as early as mid-century in order to 
prevent warming that could change precipitation patterns and dry up 
sources of water worldwide.

Using advanced computer models to factor in deep-sea warming and other 
aspects of the carbon cycle that naturally creates and removes carbon 
dioxide (CO2), the scientists, from countries including the United 
States, Canada 
<http://www.washingtonpost.com/ac2/related/topic/Canada?tid=informline> 
and Germany 
<http://www.washingtonpost.com/ac2/related/topic/Germany?tid=informline>, 
are delivering a simple message: The world must bring carbon emissions 
down to near zero to keep temperatures from rising further.

"The question is, what if we don't want the Earth to warm anymore?" 
asked Carnegie Institution senior scientist Ken Caldeira, co-author of a 
paper published last week in the journal Geophysical Research Letters. 
"The answer implies a much more radical change to our energy system than 
people are thinking about."

Although many nations have been pledging steps to curb emissions for 
nearly a decade, the world's output of carbon from human activities 
totals about 10 billion tons a year and has been steadily rising.

For now, at least, a goal of zero emissions appears well beyond the 
reach of politicians here and abroad. U.S. leaders are just beginning to 
grapple with setting any mandatory limit on greenhouse gases. The Senate 
is poised to vote in June on legislation that would reduce U.S. 
emissions by 70 percent by 2050; the two Democratic senators running for 
president, Hillary Rodham Clinton 
<http://projects.washingtonpost.com/congress/members/c001041/> (N.Y. 
<http://www.washingtonpost.com/ac2/related/topic/New+York?tid=informline>) 
and Barack Obama 
<http://projects.washingtonpost.com/congress/members/o000167/> (Ill.), 
back an 80 percent cut. The Republican presidential nominee, Sen. John 
McCain <http://projects.washingtonpost.com/congress/members/m000303/> 
(Ariz. 
<http://www.washingtonpost.com/ac2/related/topic/Arizona?tid=informline>), 
supports a 60 percent reduction by mid-century.

Sen. Barbara Boxer 
<http://projects.washingtonpost.com/congress/members/b000711/> 
(D-Calif.), who is shepherding climate legislation through the Senate as 
chairman of the Environment and Public Works Committee, said the new 
findings "make it clear we must act now to address global warming."

"It won't be easy, given the makeup of the Senate, but the science is 
compelling," she said. "It is hard for me to see how my colleagues can 
duck this issue and live with themselves."

James L. Connaughton 
<http://www.washingtonpost.com/ac2/related/topic/James+L.+Connaughton?tid=informline>, 
who chairs the White House Council on Environmental Quality, offered a 
more guarded reaction, saying the idea that "ultimately you need to get 
to net-zero emissions" is "something we've heard before." When it comes 
to tackling such a daunting environmental and technological problem, he 
added: "We've done this kind of thing before. We will do it again. It 
will just take a sufficient amount of time."

Until now, scientists and policymakers have generally described the 
problem in terms of halting the buildup of carbon in the atmosphere. The 
United Nations' Framework Convention on Climate Change framed the 
question that way two decades ago, and many experts talk of limiting 
CO2concentrations to 450 parts per million (ppm).

But Caldeira and Oregon State University 
<http://www.washingtonpost.com/ac2/related/topic/Oregon+State+University?tid=informline> 
professor Andreas Schmittner now argue that it makes more sense to focus 
on a temperature threshold as a better marker of when the planet will 
experience severe climate disruptions. The Earth has already warmed by 
0.76 degrees Celsius (nearly 1.4 degrees Fahrenheit) above 
pre-industrial levels. Most scientists warn that a temperature rise of 2 
degrees Celsius (3.6 degrees Fahrenheit) could have serious consequences.

Schmittner, lead author of a Feb. 14 article in the journal Global 
Biogeochemical Cycles, said his modeling indicates that if global 
emissions continue on a "business as usual" path for the rest of the 
century, the Earth will warm by 7.2 degrees Fahrenheit by 2100. If 
emissions do not drop to zero until 2300, he calculated, the temperature 
rise at that point would be more than 15 degrees Fahrenheit.

"This is tremendous," Schmittner said. "I was struck by the fact that 
the warming continues much longer even after emissions have declined. . 
. . Our actions right now will have consequences for many, many 
generations. Not just for a hundred years, but thousands of years."

While natural cycles remove roughly half of human-emitted carbon dioxide 
from the atmosphere within a hundred years, a significant portion 
persists for thousands of years. Some of this carbon triggers deep-sea 
warming, which keeps raising the global average temperature even after 
emissions halt.

Researchers have predicted for a long time that warming will persist 
even after the world's carbon emissions start to fall and that countries 
will have to dramatically curb their carbon output in order to avert 
severe climate change. Last year's report of the U.N. 
<http://www.washingtonpost.com/ac2/related/topic/United+Nations?tid=informline> 
Intergovernmental Panel on Climate Change 
<http://www.washingtonpost.com/ac2/related/topic/Intergovernmental+Panel+on+Climate+Change?tid=informline> 
said industrialized nations would have to cut emissions 80 to 95 percent 
by 2050 to limit CO2concentrations to the 450 ppm goal, and the world as 
a whole would have to reduce emissions by 50 to 80 percent.

European Union Environment Commissioner Stavros Dimas, in Washington 
last week for meetings with administration officials, said he and his 
colleagues are operating on the assumption that developed nations must 
cut emissions 60 to 80 percent by mid-century, with an overall global 
reduction of 50 percent. "If that is not enough, common sense is that we 
would not let the planet be destroyed," he said.

The two new studies outline the challenge in greater detail, and on a 
longer time scale, than many earlier studies. Schmittner's study, for 
example, projects how the Earth will warm for the next 2,000 years.

But some climate researchers who back major greenhouse gas reductions 
said it is unrealistic to expect policymakers to think in terms of such 
vast time scales.

"People aren't reducing emissions at all, let alone debating whether 88 
percent or 99 percent is sufficient," said Gavin A. Schmidt, of NASA's 
Goddard Institute for Space Studies. "It's like you're starting off on a 
road trip from New York to California 
<http://www.washingtonpost.com/ac2/related/topic/California?tid=informline>, 
and before you even start, you're arguing about where you're going to 
park at the end."

Brian O'Neill of the National Center for Atmospheric Research emphasized 
that some uncertainties surround the strength of the natural carbon 
cycle and the dynamics of ocean warming, which in turn would affect the 
accuracy of Caldeira's modeling. "Neither of these are known precisely," 
he said.

Although computer models used by scientists to project changes in the 
climate have become increasingly powerful, scientists acknowledge that 
no model is a perfect reflection of the complex dynamics involved and 
how they will evolve with time.

Still, O'Neill said the modeling "helps clarify thinking about long-term 
policy goals. If we want to reduce warming to a certain level, there's a 
fixed amount of carbon we can put into the atmosphere. After that, we 
can't emit any more, at all."

Caldeira and his colleague, H. Damon Matthews, a geography professor at 
Concordia University in Montreal, emphasized this point in their paper, 
concluding that "each unit of CO2emissions must be viewed as leading to 
quantifiable and essentially permanent climate change on centennial 
timescales."

Steve Gardiner, a philosophy professor at the University of Washington 
<http://www.washingtonpost.com/ac2/related/topic/University+of+Washington?tid=informline> 
who studies climate change, said the studies highlight that the argument 
over global warming "is a classic inter-generational debate, where the 
short-term benefits of emitting carbon accrue mainly to us and where the 
dangers of them are largely put off until future generations."

When it comes to deciding how drastically to reduce greenhouse gas 
emissions, O'Neill said, "in the end, this is a value judgment, it's not 
a scientific question." The idea of shifting to a carbon-free society, 
he added, "appears to be technically feasible. The question is whether 
it's politically feasible or economically feasible."

(c) 2008 The Washington Post Company
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