The Climate Change Act of 2008 is, supposedly, underpinned by the findings of climate science, and riding herd on these findings is the Climate Change Committee (CCC), which reviews the state of climate science whenever a new carbon budget is published to see whether any significant changes have occurred. Here we briefly review the CCC’s latest assessment, which accompanies the fifth carbon budget. We find that few if any of the CCC’s conclusions are backed up by hard evidence and that some of them are the opposite of the truth. Yet they still underpin the Climate Change Act, which continues to govern the UK’s long-term energy policy.
Listed below without comment are the CCC’s conclusions on climate change, reproduced from the CCC’s fifth carbon budget report . These are the conclusions on which the UK government is basing multi-billion pound decisions:
The evidence that global warming is happening, driven by human activity and with large potential impacts, is supported by many lines of research and agreed by the world’s leading scientific bodies. Much of the information presented here is covered at length in the latest assessment by the Intergovernmental Panel on Climate Change (IPCC AR5)
It is clear that the climate is changing as a result of greenhouse gas emissions. This is leading to rising temperatures and sea levels, retreating ice and other changes to the natural environment. Global average temperature has risen around 0.9°C and sea level around 20cm since the late 19th Century:
• The basic fact that greenhouse gases in the air warm the surface of the Earth has been understood for over a century and is well-established.
• Greenhouse gases are being emitted by human activities (principally carbon dioxide from fossil fuel burning) at an increasing rate and are accumulating in the atmosphere. Emissions of other air pollutants have a net cooling influence, partially offsetting greenhouse warming to date.
• Trends in climate are also influenced by natural factors, including solar variations, volcanic eruptions and natural cycles within the climate system (such as El Niño).
• Global average surface temperature is now about 0.9°C above late-19th Century levels. Observed warming is not uniform and has led to many other changes including changes in rainfall patterns, rising sea levels and the loss of ice from Greenland and Antarctica. Carbon dioxide emissions are also acidifying the oceans.
• The pattern of global warming over the 20th Century matches that expected from natural and human factors combined, and not that from natural factors alone. Human activity has clearly been the dominant driver of global temperature rise since at least the 1950s. Many impacts are already being detected across the world, from changes in extreme weather and ecosystems to a slowdown in productivity gains for some key crops.
• Scientists are highly confident that, among other impacts, climate change is bleaching coral on reefs worldwide; greening and fruiting trees earlier in the year across Europe; reducing river flows across South Western Australia; forcing plant and animal species towards the poles and to higher elevations around the world; and negatively impacting those living in the Arctic.
• There has been a negative effect on the global growth in productivity of some key crops, with a reduction of 2 %/decade (0-5 %/decade) for wheat, and 1 %/decade (0-3 %/decade) for maize. Some crops in Europe and southern South America have experienced gains due to climate change, while South Asia and wheat in Europe have incurred losses.
• European heat waves as strong as in 2003 (when crop yields fell, power stations were shut down due to overheating and the heat-related death toll ran into tens of thousands) are estimated to have been made at least twice as likely by human activity. A recent update suggests the warming since 2003 now makes it ten times more likely to occur again.
• The coastal surge brought to Manhattan by Hurricane Sandy in 2012 was made 20cm higher by sea level rise, increasing losses in New York by 30%. In addition, the above-average sea surface temperatures at the time increased its wind speeds and rainfall.
These impacts give an indication of the widespread and pervasive nature of climate risks.
Even those with only a rudimentary knowledge of the facts will be able to find holes in these conclusions big enough to drive a bus through. Specific examples include the claim that wheat and maize crop yields are declining, which was debunked in Euan Mearns’ Food, Population and Energy post, the claim that climate change is impacting extreme weather events – something that not even the IPCC agrees with; see Roger Pielke’s post on the subject – and the claim that 20cm of sea level rise increased damage losses from Sandy by 30% in Manhattan. But not a word is said about the global warming “pause”, or about the fact that climate models no longer match observations, or about the numerous recent estimates of climate sensitivity which suggest that the IPCC’s 3 degrees C estimate may be up to two times too high.
Yet these myths and others like them, such as the Greenland ice sheet collapsing into the sea, continue to be perpetrated, and under the provisions of the Climate Change Act they continue to drag the government’s energy policy around by the nose. As to what can be done about it, the opinions of the CCC will not change as long as it remains populated entirely by greens (see the CVs in the CCC fifth carbon budget report). A faint chink of light is, however, offered by the Climate Change Act itself, which authorizes the Secretary of State to “amend the (80% by 2050 target) …. if it appears to the Secretary of State that there have been significant developments in ….. scientific knowledge about climate change.” Well, there have indeed been some significant developments since the Act was adopted in 2008, but thanks to the CCC Amber Rudd may never have been told about them. Whether her successor Greg Clark is aware of them is unknown, but if he isn’t someone should tell him.