More dangers lurking..

[stpioc]

Bit of a contrast between the report's summary and the report itself..

The report’s summary for policymakers paints a sobering picture of the potentially terrible impacts of allowing global mean surface temperature to rise by 2C compared with pre-industrial levels: more extreme weather, sea level rise and ocean acidification, with detrimental effects on wildlife, crops, water availability and human health. But the policymakers, or at least their aides, should make the effort to read the whole report. Incredibly, the stark summary is still a relatively conservative assessment of the consequences we might face if global warming does exceed 1.5C. The report is a comprehensive review of the published evidence painstakingly compiled by hundreds of authors and reviewers over the past two and a half years.

The summary of the report was approved line by line by governments, including the US, Australia and Saudi Arabia, during long and intensive discussions last week in South Korea. It is written in matter-of-fact language, but it omits some of the biggest risks of climate change, which are described in the full text. For instance, the summary indicates that warming of 2C would have very damaging impacts on many parts of the world. But it does not mention the potential for human populations to migrate and be displaced as a result, leading to the possibility of war. 

The summary also leaves out important information about so-called “tipping points” in the climate system, beyond which impacts become unstoppable, irreversible or accelerate. It acknowledges that the land-based ice sheets in Greenland and west Antarctica may be destabilised even by warming of 1.5C, ensuring several metres of sea level rise over the coming centuries. But there is no mention of other important thresholds that might, for instance, halt the Gulf Stream in the Atlantic, or cause shifts in the occurrence of the monsoons in Africa and Asia. It is not clear why such crucial information has been left out of the summary. Perhaps the authors felt that there are too many uncertainties in our knowledge to be definitive. But the danger is that policymakers will assume the absence of these very significant risks from the summary means that researchers have assessed them to be unimportant or impossible.

The IPCC global warming report spares politicians the worst details | Bob Ward | Opinion | The Guardian