Across the globe there are many observations that, taken together, demonstrate the effects of climate change. Global average temperature has increased 0.6°C since 1900, and the ten hottest years on record have been since 1990. In the UK, 2003 was the hottest year ever recorded.

Other evidence from around the world includes:

• 10% reduction in snow cover in the Northern hemisphere since the late 1960's;
• 40% reduction in Arctic sea ice in recent decades;
• Permaforst, that has been stable for thousands of years, is now thawing;
• The sea level across the globe has risen by 10-25 cm since 1900;
• Extreme weather events (floods, droughts, storms and powerful hurricanes etc) are becoming more frequent;
• Spring is happening earlier, meaning that plants are flowering and birds are laying eggs earlier each year;
• 40% reduction in Arctic sea ice in recent decades;
• Permafrost, that has been stable for thousands of years, is now thawing;
• The sea level across the globe has risen by 10-25 cm since 1900;
• Extreme weather events (floods, droughts, storms and powerful hurricanes etc) are becoming more frequent;
• Spring is happening earlier, meaning that plants are flowering and birds are laying eggs earlier each year. 

These observations may be due in part to the natural cycles of the Earth, but there is very little doubt that human activity is playing an important part.

Climate change evidence - UK