UN’s 2C target will fail to avoid a climate
disaster, scientists warn

The limit of 2C of
global warming agreed by the world’s governments is a “dangerous
target”, “foolhardy” and will not avoid the most disastrous
consequences of climate change, new research from a panel of
eminent climate scientists warned on Tuesday.

In
a new paper, the climate scientist Professor James Hansen and a
team of international experts found the most dangerous effects of a
warming climate – sea level rise, Arctic ice
melt, extreme weather – would begin kicking in with a
global temperature rise of 1C.

Allowing warming
to reach 2C would be simply too late, Hansen said. “The case we
make is that 2C itself is a very dangerous target to be aiming
for,” he told the Guardian. “Society should reassess what are
dangers levels, given the impacts that we have already
seen.”

The research, published in the peer-reviewed
journal PLoS One, represents Hansen’s most public
intervention so far into the world of climate policy, following his
retirement earlier in 2013 from Nasa’s Goddard Institute of Space
Studies.

Hansen, who left Nasa to be more free
to act as a climate advocate, set up a new climate policy programme
at the Earth Institute in September. In a separate action, he
intervened in November in support of a law suit demanding the federal government
act to cut the greenhouse gas emissions that cause
climate change.

The new study, however, was
aimed at marshalling the expertise of 17 other climate and policy
experts from the UK, Australia, France, Sweden and Switzerland as
well as the US, to outline the dangerous consequences of sticking
to the 2C warming target endorsed by the United Nations and world
leaders.

The Intergovernmental Panel on Climate
Change warned in its major in October that the world had only about
30 years left before it
exhausted the rest of the 1,000 gigaton carbon emission
budget estimated to lead to 2C warming. But Hansen and
his colleagues warned that the UN target would not avoid dangerous
consequences, even if it kept within that carbon budget.

“Fossil fuel emissions of 1,000 gigaton, sometimes
associated with a 2C global warming target, would be expected to
cause large climate change with disastrous consequences. The
eventual warming from one gigaton fossil fuel emissions likely
would reach well over 2C, for several reasons. With such emissions
and temperature tendency, other trace greenhouse gases including
methane and nitrous oxide would be expected to increase, adding to
the effect of CO2,” the researchers said.

The
paper draws on multiple strands of evidence to make its case,
including the rapid decline of Arctic sea ice, mountain glaciers,
and the Greenland and Antarctic ice sheets, the expansion of hot,
dry subtropical zones, the increase in drought and wildfires, and
the loss of coral reefs because of ocean acidification.

“The main point is that the 2C target – which is almost
out of reach now, or quickly becoming out of reach – is itself a
dangerous target because it leads to a world that is greatly
destabilised by rising sea levels and massive changes of climate
patterns in different parts of the world,” said Professor Jeff
Sachs, director of the Earth Institute at Columbia University, one
of the PLoS paper’s authors.

An even bigger
problem however was that the international community was far from
even reaching that inadequate target, Sachs said. “Right now we are
completely off track globally,” he said. “We are certainly not even
in the same world as a 1C world. We are not even in a 2C
world.”

The paper goes on to urge immediate cuts
in global emissions of 6% a year as well as ambitious reforestation
efforts to try to keep temperatures in check. The paper
acknowledges such actions would be “exceedingly difficult” to
achieve, but says it is urgent to begin reductions now, rather than
wait until future decades.

It warns that the
targets will remain far out of reach so long with continued
exploitation of fossil fuels, such as coal burning for electricity
and continued exploitation of unconventional oil and gas.

The paper also offers prescriptions, urging the adoption
of a direct carbon tax at point of production and entry. “Our
policy implication is that we have to have a carbon fee and some of
the major countries need to agree on that and if that were done it
would be possible to actually get global emissions to begin to come
down rapidly I think,” Hansen said.

The study
also calls for an expansion of nuclear power – which will be
controversial for environmental groups. Hansen has long been an
advocate for nuclear power as a solution to climate change, and he
has been critical of environmental groups for not coming on
board.

“Surely a few decades ago it made sense
to be very cautious about any further expansion of nuclear power
but a lot has happened over last few decades,” Hansen said.
“Climate change is going to be uncontrollable if we can’t get
carbon-free electricity … Environmental groups need to look at
the real world.”