Our changing climate

Climate refers to the average weather and its variability experienced over a long period, typically 30 years.

It is increasingly accepted that we are committed to man-made climate change, no matter what we do now, and in the future, to reduce our CO2 emissions.

The most comprehensive projections for global climate change are given in the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report, published in 2007. This makes it clear that urgent action is needed now both to reduce our CO2 emissions and to adapt to the inevitable impacts of climate change. The IPCC is currently starting to outline its Fifth Assessment Report (AR5) which will be finalized in 2014
Key projections for the UK from now until the end of the century (UKCP09) are:

Warmer winters with mean temperatures projected to increase from 1.4ºC to 5.7ºC

• Hotter summers with mean temperatures projected to rise from 1.4ºC to 8.2ºC
• In summer ‘hot days’ (temperatures >28ºC) that occur 2-6 days a year are projected to occur from 9-60 days per year (Medium emission scenario).  The annual highest maximum temperature is projected to be 32ºC to 40.2ºC (medium emission scenario)
•  Winter mean precipitation is projected to increase from 3 to 58 per cent; and
•  Summer mean precipitation is projected to be predominately drier with changes from -56 to +13 per cent
• Sea-levels will continue to rise, with a projected central estimate of 37.1 to 53.1 cm above 1990 levels

 

What’s already happening?

These changes will mean that the likelihood of ‘extreme weather’ such as droughts, heatwaves and flooding will increase. Observations show that we are already experiencing some of these projected changes;

• The first decade of this century has been, by far, the warmest decade on instrumental record with ten of the warmest years on record have occurred since 1995, with July 2006 being the warmest month on record, autumn 2006 the warmest autumn, and April 2007 the warmest April
• The hottest ever maximum temperature in the UK was recorded in August 2003 (38.5ºC at Faversham, Kent)
• The average duration of summer heat waves has increased by 4–16 days in all regions of the UK since 1961
• There has been a general trend of decreasing rainfall in summer and increasing rainfall in winter with heavier winter precipitation events.
• Sea levels around the UK have risen by 10cm since 1900.