Yesterday, two scientists published a
stern critique of the longstanding target to limit global
warming to two degrees above pre-industrial levels.
Branding the target "wrong-headed" and "tenuous", the
authors argue we should ditch the two degree target in favour of a
suite of "vital signs" that would let us track the Earth's
commentary, published in the journal Nature, has
interest. We asked climate scientists for their thoughts.
Setting a target
In 1992, the United Nations Framework Convention on
Climate Change (UNFCCC)
decided the objective of
global climate policy should be to stabilise humans' influence on
the climate below the level at which it can be considered
As temperatures rise, so do the risks of climate
change. As the recent
report on climate change impacts from
the Intergovernmental Panel on Climate Change (IPCC) puts
"Increasing magnitudes of
warming increase the likelihood of severe, pervasive, and
With governments worldwide recognising the need to
keep rising temperatures in check, it's important to have a goal,
Professor Nigel Arnell, director of the Walker Institute for
Climate System Research, tells us:
"When we're trying to work out
what future climate change might do and how to reduce it, you need
some form of metric or indicator on order to judge how well
particular policies achieve that goal."
A good indicator
Curbing temperature rise has been central tenet of
climate policy for two decades. One of Victor and Kennel's main
criticisms in the Nature commentary is the international
community's narrow focus on temperatures at earth's surface.