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1.5°C or 2°C: a conduit’s view from the science-policy interface at COP20 in Lima, Peru

In its Friday issue from 27 March "Science Daily " featured a research in which a lead author on the Intergovernmental Panel on Climate Change (IPCC), writing a commentary in the open access journal "Climate Change Responses", says that: "The official global target of a 2°C temperature rise is 'utterly inadequate' for protecting those at most risk from climate change" .

The author Petra Tschakert from The Pennsylvania State University and a coordinating lead author of the IPCC's Fifth Assessment Report says: "The consensus that transpired during this session was that a 2°C danger level seemed utterly inadequate given the already observed impacts on ecosystems, food, livelihoods, and sustainable development.

  • The commentary presents a rare inside-view of a discussion at the Lima Conference of the Parties on the likely consequences of accepting an average global warming target of 2 degrees Celsius versus 1.5 degrees Celsius.
  • The 2°C 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.
  • "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."

In her commentary, Tschakert explains that the target of keeping the global average temperature rise to below 2°C 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.