Know Climate Change

Science behind Climate Change


Changes in Earth’s Average Temperature

The temperature increase has been widespread over the globe and is greater at higher northern latitudes.

The following graph shows how global temperature has changed over time from 1850.

Changes in the earth’s average temperature from 1850 onwards – for recent periods, the slope is greater, indicating accelerated warming. The shaded areas are the uncertainty intervals estimated from a comprehensive analysis of known uncertainties.
Source: IPCC 2007

You can view an animation depicting projected temperature rise at Hadley Centre.

Average Northern Hemisphere temperatures during the second half of the 20th century were very likely higher than during any other 50-year period in the last 500 years, and likely the highest in at least the past 1300 years (IPCC 2007).
Warming has been more significant over land areas than in oceans. In the last two decades, while warming over the land has occurred at the rate of 0.27 °C per decade, oceans have warmed by 0.13 °C per decade.

The average temperature of the earth's surface has risen by 0.74 °C since the late 1800s. It is expected to increase by another 1.8 °C to 4 °C by the year 2100, which is very alarming and would result in rapid and profound change if necessary action is not taken. Even if the minimum predicted increase takes place, it will be larger than any century-long trend in the last 10,000 years.