Conclusion of the IPCC 5th Assessment Report: Climate change threatens irreversible and dangerous impacts, but options exist to limit its effects
The Intergovernmental Panel on Climate Change (IPCC) concluded its Fifth Assessment Report on 2 November 2014 with the release of its Synthesis Report. The Synthesis Report distils and integrates the findings of the IPCC Fifth Assessment Report produced by over 800 scientists and released over the past 13 months - the most comprehensive assessment of climate change ever undertaken.
Some of the key conclusions from the report are that:
- human influence on the climate system is clear and growing
- impacts of climate change have been observed on all continents
- if left unchecked, climate change will increase the likelihood of severe, pervasive and irreversible impacts for people and ecosystems
- many options are available to adapt to climate change and to reduce greenhouse gas emissions to ensure the risks from climate change remain manageable, creating a brighter and more sustainable future.
IPCC report authors met with government representatives in Copenhagen during the last week of October to finalise the "Summary for Policymakers" of the report. IPCC Chair Dr Pachauri opened the meeting by saying the report points to solutions to tackle climate change. "We still have time to avoid the most serious impacts of climate change," he said. "But we have precious little of that time".
The Synthesis Report says it is 95% certain that emissions of greenhouse gases and other anthropogenic drivers have been the dominant cause of observed warming since the mid-20th century, and recent climate changes (regardless of their cause) have already had widespread impacts on human and natural systems. Continued emissions of greenhouse gases will cause further warming and long-lasting changes in climate system, increasing the likelihood of widespread and profound impacts affecting all levels of society and the natural world, the report finds.
Two climate scientists associated with the New Zealand Climate Change Centre participated in the meeting. Dr Andy Reisinger, Deputy Director of the New Zealand Agricultural Greenhouse Gas Research Centre was a member of the core writing team for the draft report, and Dr David Wratt of NIWA and Victoria University attended as a member of the IPCC Bureau.
The Synthesis Report makes a clear case that challenges are particularly large for least developed countries and vulnerable communities, including marginalized people within countries, given their more limited ability to cope.
The report finds that adapting to climate change can play a key role in addressing these risks, but there are limits to its effectiveness, especially with greater magnitudes and rates of climate change. Substantial and sustained reductions of greenhouse gas emissions are at the core of limiting the risks of climate change. Dr Reisinger says: "Reducing emissions reduces the rate as well as the magnitude of warming; this not only reduces its impacts but also increases the time available for adaptation to a particular level of climate change, potentially by several decades."
Substantial emissions reductions over the next few decades, with near-zero global emissions of CO2 by the end of the 21st century, would be needed to limit warming to 2°C above preindustrial levels - the goal set by Governments. Dr Reisinger says: "Implementing such reductions poses substantial technological, economic, social and institutional challenges, and there are multiple paths for how we could achieve that goal. But the challenges will increase if we delay additional global mitigation to 2030 or exclude some technologies".
The report offers a strong recognition that international cooperation is crucial for effective global reductions in greenhouse gas emissions, but that cooperation across and within countries can also enhance efforts to adapt to climate change.
The meeting was attended by 34 lead authors of the report and 270 government delegates from 114 countries to negotiate and approve the wording of the report summary, including a New Zealand Government delegation comprising officials from the Ministry for the Environment.
Full text of the IPCC Synthesis Report is available on the IPCC website www.ipcc.ch
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