Thursday, December 10, 2015
CoP 21 Update: Leading Scientists call for 1.5 Degree Pathway!
23 IPCC and Leading Scientists Call for Greater Ambition and 1.5 Degree Pathway
A group of 23 leading scientists has called for greater reductions to avoid crossing dangerous thresholds in “cryosphere” – snow and ice – regions, stressing the need for a 1.5 degree pathway to constrain risk. The statement is based on the findings of the Inter-Governmental Panel on Climate Change (IPCC)’s Fifth Assessment, but takes into account important research published since that sharpens concerns about dynamics that might be triggered within the next few decades, especially in West Antarctica. This includes the risk of 4-5 meters committed or “irreversible” sea-level rise that would unfold over many centuries, but could be impossible to halt once begun.
The scientists, 13 of them IPCC authors, others senior and cutting-edge researchers, note, "... This can set into motion very long-term changes that cannot be stopped or reversed, even if temperatures later decrease. Some changes, such as committed sea-level rise from the great polar ice sheets, cannot be reversed short of a new Ice Age.”
These potentially irreversible risks include mountain glaciers, 80% of which can be expected to disappear at current pledges or INDCs; sea-level rise from the ice sheets of Greenland and Antarctica; permafrost thaw and related carbon release, which may eat one-third to one-half of current carbon budgets at existing INDCs; Arctic summer sea ice loss; and serious polar ocean acidification, which is occurring even faster in these waters than in oceans at lower latitudes.
As a result of these risk-filled dynamics, as negotiations move into their final stages the scientists urge a focus on actions that will lead to temperatures preferably under 1.5 degrees over pre-industrial, for the best chance of limiting these risks.
Source: email from Pam Pearson, Director, International Cryosphere Climate Initiative (ICCI)