Global temperature (in °C) from 1900 to 2009. The black line is the annual global mean. The red line is the 10-year running mean. The grey area shows the 95% confidence interval calculated for the 50 years up to and including each year's measurement. The graph shows an increase in mean global temperature, an increase in the confidence interval (i.e. warmer climate) and an increase in the width of the confidence interval (i.e. more variable temperatures). Data from the Hadley Centre for Climate Change, U.K. Graph constructed by Hanno Sandvik, Norwegian University of Science & Technology.