Climate change mitigation - Why care? (United Kingdom)

·         Central England Temperature (CET) has risen by about 1°C since 1980. Eight of the ten warmest years recorded have been since 1990 with 2006 being the warmest year on record. It is likely that there has been a significant influence from human activity on the recent warming of CET. Average annual temperature for all regions of the UK has risen by between 0.4°C and 0.9°C since 1914.

·         Severe windstorms around the UK have become more frequent in the past few decades, although not above the frequency in the 1920s.

·         Sea level around the UK rose by about 1mm/yr in the 20^th century, corrected for land movement. The rate for the 1990s and 2000s has been higher, up to 3mm/yr, which is closer to the global average for these years. Sea-surface temperatures around the UK coast have risen by about 0.7°C over the past three decades.

·         Annual mean precipitation over England and Wales has not changed significantly since records began in 1766. Scotland is on average 20 per cent wetter than it was in 1961. Seasonal rainfall is highly variable, but appears to have decreased in summer and increased in winter.

·         All regions of the UK have experienced more winter rainfall from heavy precipitation events. In summer, all regions except North East England and Northern Scotland show decreases in rainfall.

The subset of key findings presented below is for a medium emissions pathway and may be exceeded if we do not secure an ambitious, lasting global deal to limit emissions.

In general, greater warming is expected in the southeast than the northwest of the UK, and there may be more warming in the summer and autumn than winter and spring. Projections of average summer temperature change in the South East get larger over time, with projected increases in average summer temperatures of 1.6°C during the 2020s, 2.7°C by the 2040s and 3.9°C by the 2080s.

But while this is the average, there will be a big change in rainfall between the seasons, with winters becoming wetter and summers drier.

Under the medium emissions scenario, by the 2080s, rainfall in the South West may be 23 per cent lower in the summer, and 16 per cent higher in the North East in the winter.

The central estimate for sea level rise (taking into account land movement) highlights that sea level is projected to rise by 36cm in London by the 2080s.

High summer temperatures and dry conditions are likely to become more common. For example, research published by the Met Office Hadley Centre suggests that the summer heat wave we experienced in 2003 could become a normal event by the 2040s; by the 2060s, such a summer would be considered cool according to some models. And though very cold winters will become increasingly rare, extreme winter rainfall will become more frequent.