Weather and climate

Atmospheric weather and climate have important effects on the ocean, influencing its temperature, salinity and circulation patterns on short and long timescales, respectively. For this assessment we have studied variability and trends in these factors using direct observations from the UK and world-wide.

There have been significant changes over the past few decades. The global surface air temperature has risen by about 0.75 °C since the late 19th century, 0.15 °C more than estimated in Charting Progress (some more warm years since then have affected trend assessments). The ten warmest years since global records began in 1850 all occurred between 1997 and 2008. The Central England Temperature has risen by about 1 °C since the beginning of the 20th century, as have annual mean air temperatures over Wales, Northern Ireland and Scotland. 2006 was the warmest year in central England since records began in the 17th century. Most of this rise was very probably caused by increases in human greenhouse gas emissions.

The average number of winter storms recorded at UK stations has increased significantly over the past 50 years. However, this has largely balanced a decline in the first half of the 20th century. Winters are continuing to become wetter in northern and western Scotland. Two out of the five wettest UK summers since records began in 1766 were in 2007 and 2008.