Committee on Climate Change

Global Climate Risks

There is a high level of certainty that warming is occurring due to human activity. It is also clear that warming will increase as emissions continue. Despite this, projections about the exact future level of warming and its consequences at local scales are complex and involve greater uncertainty.

One aspect of complexity comes from the simulating the whole climate system. All parts of the climate system – the atmosphere, the land surface, rivers and oceans, snow and ice and ecosystems – are linked together through interacting processes. Climate projections attempt to capture these processes, but some of them are better characterised than others.

Because of these interactions, a warming planet will lead to many other climate changes, such as:

• changing precipitation patterns
• sea level rise
• changes in the intensity of extreme weather (storms, droughts, heatwaves, etc.)
• loss of snow and ice from mountains and polar regions
• acidification of the oceans as they absorb more carbon dioxide migrations and extinctions of plant and animal species.

Processes and Interactions affecting the climate system

 
Another aspect of complexity comes from the need to project human socio-economic development in order to quantify impacts. Socio-economic factors will determine the future path of GHG emissions and the adaptability of people to changes in climate.

Taking these uncertainties into account, the IPCC gives a likely range of 1.8-7.1°C warming above pre-industrial levels by 2100 (i.e. two to nine times greater than has been experienced so far). It also identified a number of risks across sectors as temperatures increase over the next century:

Click on the image to see a larger version
Source: Adapted from Intergovernmental Panel on Climate Change 4th Assessment (2007).

These impacts will not be distributed evenly across the world. Small islands, the tropics and polar regions are most vulnerable, but all regions will be at risk if warming continues:



Click on the image to see a larger version
Source: Adapted from Intergovernmental Panel on Climate Change 4th Assessment (2007)

Risks to the UK

Climate prediction becomes more difficult when looking beyond global changes to smaller scales. Despite this, there are emerging findings about what climate change might mean for the UK.

Agriculture, housing, flood risk, biodiversity, energy supply and demand, water availability and health are all likely to be affected. Even if global temperatures are stabilised around 2°C, the UK will still feel some consequences along with the rest of the world.

The Adaptation Sub-Committee of the CCC provides independent advice to the UK Government on preparing for climate change in the UK.