IPCC climate change report : main points

UN panel says human influence on changing of climate system is now ‘clear’

The UN’s Intergovernmental Panel on Climate Change has issued its fifth assessment report today. Here are its main points.

* Warming of the climate system is “unequivocal”, and the human influence on changing it is now “clear”.

* The period from 1983 to 2012 was likely the warmest 30-year period of the last 1,400 years in the Northern Hemisphere.

* Atmospheric concentrations of carbon dioxide, methane and nitrous oxide are “unprecedented in at least the last 800,000 years”.

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* Tackling climate change will require “substantial and sustained reductions” in greenhouse gas emissions to limit the risks.

* Without additional mitigation, warming poses a high risk of severe, widespread, and irreversible impacts globally by 2100.

* Delaying action will “substantially increase the challenges” to limit global warming below 2 degrees, relative to pre-industrial levels.

*Surface temperature is projected to rise over the 21st century under all emission scenarios, with much of it occurring in the oceans.

*Heat waves are likely to occur more often and last longer, and extreme precipitation events will become more intense and frequent.

*If temperatures were to rise above 4 degrees, risks include “substantial species extinction” as well as global and regional food insecurity.

*Impacts are projected to slow down economic growth, make poverty reduction more difficult and further erode food security,

*Climate change is expected to lead to increases in ill-health in many regions, especially in low-income developing countries.

*Without additional mitigation, warming poses a high risk of severe, widespread, and irreversible impacts globally by 2100.

*Emissions can be “substantially reduced” through changes in consumption patterns and adoption of energy savings measures.

Frank McDonald

Frank McDonald

Frank McDonald, a contributor to The Irish Times, is the newspaper's former environment editor