The greenhouse gas emissions from human activities are driving climate change and continue to rise. They are now at
their highest levels in history. Global emissions of carbon dioxide have increased by almost 50% since 1990.
The atmospheric concentrations of carbon dioxide, methane, and nitrous oxide have increased to levels unprecedented
in at least the last 800,000 years. Carbon dioxide concentrations have increased by 40% since pre-industrial times,
primarily from fossil fuel emissions and secondarily from net land use change emissions. The ocean has absorbed
about 30% of the emitted anthropogenic carbon dioxide, causing ocean acidification.
Each of the last three decades has been successively warmer at the Earth’s surface than any preceding decade
since 1850. In the Northern Hemisphere, 1983-2012 was likely the warmest 30-year period of the last 1,400 years.
From 1880 to 2012, average global temperature increased by 0.85°C. Without action, the world’s average surface
temperature is projected to rise over the 21st century and is likely to surpass 3 degrees Celsius this century – with
some areas of the world, including in the tropics and subtropics, expected to warm even more. The poorest and
most vulnerable people are being affected the most.
The rate of sea level rise since the mid-19th century has been larger than the mean rate during the previous
two millennia. Over the period 1901 to 2010, global mean sea level rose by 0.19 [0.17 to 0.21] meters.
From 1901 to 2010, the global average sea level rose by 19 cm as oceans expanded due to warming and melted ice.
The Arctic’ssea ice extent has shrunk in every successive decade since 1979, with 1.07 million km² of ice loss every decade.
It is still possible, using an array of technological measures and changes in behaviour, to limit the increase in global
mean temperature to two degrees Celsius above pre-industrial levels.
There are multiple mitigation pathways to achieve the substantial emissions reductions over the next few decades
necessary to limit, with a greater than 66% chance, the warming to 2ºC – the goal set by governments. However,
delaying additional mitigation to 2030 will substantially increase the technological, economic, social and institutional
challenges associated with limiting the warming over the 21 century to below 2 ºC relative to pre- industrial levels.
India has committed to reduce the emissions intensity of its GDP by 20 to 25% by 2020.