Delaying global action on climate change by 20 more years will put the
goal of keeping the world relatively cool out of reach forever, no
matter how much money humanity later spends to try to solve the problem,
a new study finds.
Since the 1990s, scientists and international negotiators have aimed to keep global temperatures from warming more than 2 degrees Celsius (3.6 degrees Fahrenheit), but little progress has been made so far in concrete steps toward that goal. The most recent climate talks, in Qatar in December, ended with only modest steps that fail to address growing greenhouse gas emissions, climate scientists said.
It's these delays that ultimately make dealing with climate change more
expensive and perhaps eventually impossible, according to a study
published this week (Jan. 4) in the journal Nature. While it's true
there are still uncertainties about how the climate will respond to
specific strategies, these uncertainties are nothing compared with
potential disaster caused by delay, said study researcher Joeri Rogelj
of Switzerland's Institute for Atmospheric and Climate Science in
"The uncertainties about how the climate system will respond have been
previously used as an argument to postpone action until we have learned
more," Rogelj told LiveScience. "We show that such a delay strategy is
unsupported and that the most important factor for staying below 2 degrees C is the timing of when we start tackling this problem at a global scale."
Many researchers have attempted to weigh the costs and benefits of
climate-change strategies ranging from a carbon tax on emissions to
requirements for sequestering carbon underground
rather than releasing it into the atmosphere. What Rogelj and his
colleagues did differently was to rank the importance of "the known
unknowns." These are the uncertainties that keep scientists from
predicting exactly how the future of climate will unravel. They include
geophysical uncertainties — how the climate system of our planet will
respond to specific strategies — as well as social uncertainties, such
as future growth and energy demand. Technological uncertainties include
what innovations will be available for lowering emissions. And finally,
there are the political uncertainties: When will the world decide to act
to prevent further warming? (8 Ways Global Warming Is Already Changing the World)
For the first time, Rogelj and his colleagues quantified and ranked the
importance of each of these uncertainties. They found that politics
In other words, the timing of climate-change action plays a more
important role in keeping the planet from possibly catastrophic warming
than social, geophysical or technological hurdles. If humanity delays in
taking action, even the best-case social, geophysical and tech
scenarios will do little good.
"When delaying action by two more decades, chances to stay below 2
degrees C become very low and we find that they cannot be improved later
on, no matter how much money we throw at the problem in the future,"
Without drastically reducing energy demands, two decades of delay will
mean only a 20 percent chance of staying below 2 degrees C, Rogelj said.
A move toward a highly energy-efficient society would increase those
odds to 50 percent. (The Reality of Climate Change: 10 Myths Busted)
In fact, conservation and energy efficiency (social and technological
uncertainties) play big roles in making mitigation strategies such as
carbon taxes or carbon capture more effective, the researchers found.
For example, if carbon emissions were immediately taxed at $40 a metric
ton, there would be an 80 percent chance of staying below 2 degrees in
an energy-efficient world. The same carbon price would give only a 66
percent chance of hitting that temperature goal in an
intermediate-demand world. In a future with a high demand for energy (20
percent greater than the intermediate scenario), carbon would have to
cost $150 per metric ton just to reach that same 66 percent likelihood.
A low-energy future has upsides beyond climate mitigation, Rogelj said.
"If one can continue to prosper in the future and deliver the same services with less overall energy,
this will in the first place save you money, but also very
significantly improve your national energy security situation," he said.
"It seems to me that such benefits should be appealing to any
decision-maker who cares about the long-term development and prosperity
of his or her country."
Even though the study examined more than 700 future climate scenarios,
there are some limitations to its analysis. The research didn't take
into account the cost of disasters such as coastal flooding if climate
change is not mitigated. Nor did it consider "runaway climate change"
scenarios. For example, if the melting of the permafrost releases
trapped methane stores into the atmosphere, that gas could trap heat
even more efficiently than carbon dioxide, sending temperatures soaring
faster than expected.
The researchers' middle-of-the-road predictions for economic growth
and population growth are also "somewhat optimistic," according to
Steve Hatfield-Dodds of Australian National University, who was not
involved in the study. That could mean that the estimated likelihoods of
climate-mitigation success are also optimistic, Hatfield-Dodds wrote in
an editorial accompanying the study in Nature.
Nevertheless, "the findings should help to make risks and consequences
more transparent, and thereby support better-informed economic and
political decisions," Hatfield-Dodds wrote.
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