There has been a gradual warming of the atmosphere due to human activity, and the average global temperature has risen about 0.8 degree Celsius over the past 100 years, an expert said Thursday.
"Major studies by the Intergovernmental Panel on Climate Change have carefully examined over 100 years of measurements and concluded that the average global temperature has risen about 0.8 degree Celsius," Indian Institute of Astrophysics's former director Siraj Hasan said, delivering the 13th Darbari Seth Memorial Lecture, organised by The Energy and Resources Institute (TERI), here.
"The years 1983-2012 have likely been the warmest 30 years in the last 1,400 years. The gradual temperature increase is related to the emission of greenhouse gases such as CO2 (carbon dioxide) and most likely human activity," he said.
Hasan said that in about three billion years, the outer atmosphere of the sun will begin to swell so much that earth's own atmosphere will heat up. Eventually the sun's outer layers will envelop Mercury, Venus and probably Earth as well.
Speaking on the occasion, TERI Director General R.K. Pachauri paid tributes to Darbari Seth, terming him a brilliant engineer, a remarkable leader and an innovator in every aspect of industrial activity.
The Darbari Seth Memorial Lecture held each year gets leaders of various professions to present their knowledge and articulate a vision for this country.
Delivering the presidential address, Minority Affairs Minister Najma Heptulla said the government was keen to focus on the widespread use of technologies, including swadeshi innovations.
