1 December 2009
Scientific insights UN climate panel still valid; risks need attention
Scientific insights into climate change that form the basis of the negotiations in Copenhagen are still valid. There are no grounds to doubt the conclusions in the report that was published by the UN organisation for climate analysis, in 2007. Since then, observations have been made that could indicate either an acceleration or a deceleration of global warming. However, it is too early to draw final conclusions. What is lacking in the UN report is any attention paid to the risks of a faster acceleration of climate change. These scenarios are less likely, but would have large consequences if they were to eventuate.
Such is concluded in the report ‘News in Climate Science and Exploring Boundaries’, published by the Netherlands Environmental Assessment Agency, in collaboration with the Royal Netherlands Meteorological Institute (KNMI) and the Wageningen University and Research Centre (WUR). The report has been made at the request of Minister Cramer of the Dutch ministry of Environment. The report investigated possible new insights that would lead to an adjustment of the conclusions of the Intergovernmental Panel on Climate Change (IPCC). It contains an analysis of the scientific literature published since then.
Acceleration or deceleration of global warming
The report shows that global warming is continuing. The IPCC’s conclusions on human influence in this regard are still valid. Over the last 10 years, global average temperatures have been increasing at a slower rate, although eight of the ten warmest years on record occurred in the period since 2000. The Greenland and Antarctic Ice Sheets are melting at a faster rate than was estimated in 2007, and the surface area and thickness of the sea ice in the North Pole area are ever decreasing. However, in the coming decades, the sun is expected to become less active than it is today; this could slow down global warming in the coming 20 to 30 years with 0.2 °C. Nevertheless, researchers say that it is too early to draw any conclusions from these observations, for the long term. Therefore, the IPCC scenarios up to 2100 will remain valid, for now.
Warning signs
The IPCC report assumes the most likely scenario for climate change. PBL, however, states that some attention needs to be paid to the risks involved in scenarios of faster global warming. Although the chances of such increased global warming are slight, global or local effects could be very large. For instance, it could lead to dieback of the Amazon rainforest and the boreal forests. The report recommends looking for warning signs that provide early indication of an acceleration of climate change, as well as recognising its possible effects. The PBL also suggests that further research be done into the policy measures meant to deal with these types of risks, such as those limiting greenhouse gas emissions, or those aimed at adaptation to climate change.
Consequences for the Netherlands
The report indicates that the Netherlands is adequately prepared for any events related to extreme sea level rise and river floodings. The PBL advises that, in addition to this, further research is done around the effects of an accelerated climate change on human health, agriculture and nature.
To the publication: News in climate science and exploring boundaries
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The Netherlands Environmental Assessment Agency (PBL) is the national institute for strategic policy analysis in the field of environment, nature and spatial planning. We contribute to improving the quality of political and administrative decision-making by conducting outlook studies, analyses and evaluations in which an integrated approach is considered paramount. Policy relevance is the prime concern in all our studies. We conduct solicited and unsolicited research that is always both independent and scientifically sound.
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