Executive Summary
Observed Changes in Global Climate
The global average temperature
1 has risen by around 1°C since pre-industrial times. This
magnitude and rate of warming cannot be explained by natural variations alone and must
necessarily take into account changes due to human activities. Emissions of greenhouse gases
(GHGs), aerosols and changes in land use and land cover (LULC) during the industrial period
have substantially altered the atmospheric composition, and consequently the planetary energy
balance, and are thus primarily responsible for the present-day climate change. Warming since
the 1950s has already contributed to a significant increase in weather and climate extremes
globally (e.g., heat waves, droughts, heavy precipitation, and severe cyclones), changes in
precipitation and wind patterns (including shifts in the global monsoon systems), warming and
acidification of the global oceans, melting of sea ice and glaciers, rising sea levels, and
changes in marine and terrestrial ecosystems.
Projected Changes in Global Climate
Global climate models project a continuation of human-induced climate change during the
twenty-first century and beyond. If the current GHG emission rates are sustained, the global
average temperature is likely to rise by nearly 5°C, and possibly more, by the end of the
twenty-first century. Even if all the commitments (called the “Nationally Determined Contributions”) made under the 2015 Paris agreement are met, it is projected that global warming
will exceed 3°C by the end of the century. However, temperature rise will not be uniform
across the planet; some parts of the world will experience greater warming than the global
average. Such large changes in temperature will greatly accelerate other changes that are
already underway in the climate system, such as the changing patterns of rainfall and
increasing temperature extremes.
Climate Change in India: Observed and Projected Changes
Temperature Rise Over India
India’s average temperature has risen by around 0.7°C during 1901–2018. This rise in temperature is largely on account of GHG-induced warming, partially offset by forcing due to
anthropogenic aerosols and changes in LULC.
1
Unless otherwise specified, “temperature” refers to the sea surface temperature (SST) for oceanic areas and
near surface air temperature over land areas.
xiii
Observed Changes in Global Climate
The global average temperature
1 has risen by around 1°C since pre-industrial times. This
magnitude and rate of warming cannot be explained by natural variations alone and must
necessarily take into account changes due to human activities. Emissions of greenhouse gases
(GHGs), aerosols and changes in land use and land cover (LULC) during the industrial period
have substantially altered the atmospheric composition, and consequently the planetary energy
balance, and are thus primarily responsible for the present-day climate change. Warming since
the 1950s has already contributed to a significant increase in weather and climate extremes
globally (e.g., heat waves, droughts, heavy precipitation, and severe cyclones), changes in
precipitation and wind patterns (including shifts in the global monsoon systems), warming and
acidification of the global oceans, melting of sea ice and glaciers, rising sea levels, and
changes in marine and terrestrial ecosystems.
Projected Changes in Global Climate
Global climate models project a continuation of human-induced climate change during the
twenty-first century and beyond. If the current GHG emission rates are sustained, the global
average temperature is likely to rise by nearly 5°C, and possibly more, by the end of the
twenty-first century. Even if all the commitments (called the “Nationally Determined Contributions”) made under the 2015 Paris agreement are met, it is projected that global warming
will exceed 3°C by the end of the century. However, temperature rise will not be uniform
across the planet; some parts of the world will experience greater warming than the global
average. Such large changes in temperature will greatly accelerate other changes that are
already underway in the climate system, such as the changing patterns of rainfall and
increasing temperature extremes.
Climate Change in India: Observed and Projected Changes
Temperature Rise Over India
India’s average temperature has risen by around 0.7°C during 1901–2018. This rise in temperature is largely on account of GHG-induced warming, partially offset by forcing due to
anthropogenic aerosols and changes in LULC.
1
Unless otherwise specified, “temperature” refers to the sea surface temperature (SST) for oceanic areas and
near surface air temperature over land areas.
xiii