2 degree Celsius climate change target “utterly inadequate”

Tuesday, March 31, 2015 - 9:23am

The official global target of a 2-degree Celsius temperature rise is “utterly inadequate” for protecting those at most risk from climate change, says a lead author on the Intergovernmental Panel on Climate Change (IPCC), writing a commentary in the open access journal Climate Change Responses.

Access the article here: http://dx.doi.org/10.1186/s40665-015-0010-z

Petra Tschakert, a coordinating lead author of the IPCC’s Fifth Assessment Report, says: “The consensus that transpired during this session was that a 2-degree Celsius danger level seemed utterly inadequate given the already observed impacts on ecosystems, food, livelihoods, and sustainable development.

“A low temperature target is the best bet to prevent severe, pervasive, and potentially irreversible impacts while allowing ecosystems to adapt naturally, ensuring food production and security, and enabling economic development to proceed in a sustainable manner.”


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The commentary presents a rare inside-view of a two-day discussion at the Lima Conference of the Parties (COP) on the likely consequences of accepting an average global warming target of 2-degree Celsius versus 1.5-degree Celsius (measured from pre-industrial times until 2100).
The discussions were part of the United Nations Framework Convention on Climate Change (UNFCCC) structured expert dialogue in December 2014. They reveal unevenly distributed risks and political power differentials between high-income countries insisting on a 2-degree Celsius target and low- and many middle-income countries pushing for 1.5-degree Celsius or lower. The 2-degree Celsius target has been said to carry an increased risk of sea level rise, shifting rainfall patters and extreme weather events such as floods, droughts, and heat waves, particularly targeting the Polar Regions, high mountain areas, and the Tropics.

In her commentary, Tschakert explains that the target of keeping the global average temperature rise to below 2-degree Celsius originates from early studies in the 1970s. This target became anchored in policy debates over the decades, and was officially sanctioned as the long-term global goal for greenhouse gas emission reductions at the COP15 in Copenhagen in 2009.

Despite support from high and upper middle-income countries with high emissions, the 2-degree Celsius target has been subject to repeated criticism from climate scientists, economists, and political and social scientists.

Alliances representing over 70 percent of the parties around the table, including over 100 low- and middle-income countries and small island states, have repeatedly said that a 2-degree Celsius rise is unsafe for their communities, and insist on a long-term goal to keep global average temperatures below 1.5-degree Celsius. These states include the Pacific nation of Tuvalu that was recently hit by Cyclone Pam.

While the 2-degree Celsius target is now being re-evaluated, no reference to an explicit 1.5-degree Celsius target is included in the 2014 Lima Call for Climate Action, despite specific remarks on the lower temperature limit being made throughout the negotiations.

Having taken part in the latest structured expert dialogue in Lima, Peru, with country delegates to the COP, fellow IPCC authors and representatives from UN agencies and intergovernmental organizations, Tschakert now shares new insights into the ongoing debate on the adequacy of the long-term goal.

A representative of the World Health Organization at the session stressed that there was no safe limit for health, as current impacts and risks from climate change were already unacceptable, impacting people’s health significantly and inequitably.  This includes a rise in undernutrition, food- and water-borne infections, and excess deaths during heat waves, of which 10,000 have already been attributed to the 2010 Russian heat wave.

Tschakert says: “Using a figure for average global warming may indeed be the most convenient and compelling means to discuss the severity of climate change impacts, but not only does it inadequately capture the complexity of the climate system, it poorly reflects locally experienced temperature increases and the extreme and large variation across regions – no single person or any species faces a global average.”

Tschakert concludes in her commentary:  “The crux of the matter is no longer about the scientific validity of one temperature target over another… It is first and foremost about overcoming deeply entrenched divisions on value judgments, responsibility, and finance.... It is about acknowledging that negative impacts of climate change under a 0.8-degree Celsius temperature increase are already widespread, across the globe, and that danger, risk, and harm would be utterly unacceptable in a 2degree Celsius warmer world, largely for them— the mollusks, and coral reefs, and the poor and marginalized populations—even if this danger hasn’t quite hit home yet for us.