Global warming is the long-term warming of the earth’s overall temperature. Average
temperature of the earth has significantly increased within the last hundred years due
to the massive industrial evolution
Global warming occurs when greenhouse gases (CO2, CH4, N2O etc) and other air
pollutants absorb sunlight and solar radiation that have bounced off the earth’s surface.
Normally, Sun’s energy hits the Earth’s atmosphere, some of it is reflected back and the
rest is absorbed and re-radiated by the greenhouse gases. With more greenhouse gases,
heat will stick around, and it will trap the sun's warmth in the planet's lower
atmosphere causing global warming.
Evidence for warming
Year 2016 has been identified as the
warmest on record and the evidence
shows that the 20 warmest years recorded
in the past 22 years. Top four years have
been recorded in 2015 to 2018.
From 2005 to 2015 the average sea level
has been increased by 3.6mm per year
As shown in the satellite images, dramatic
decline of the sea-ice in Arctic was
observed since 1979 and in the recent
years, ice sheets in the Greenland has
experienced melting too.
Satellite data also shows the West Antarctic Ice Sheet is losing mass. A recent study
indicated East Antarctica may also have started to reduce its weight.
Patterns of warming
It is projected to occur rise in near surface air temperature throughout the polar
region of the Northern Hemisphere due to the melting of sea ice sheets and the decline
in surface albedo. Due to the greater specific heat and the limited warming of the ocean,
it is predicted that the greater warming can be observed over land areas than the ocean.
Changes of the wind pattern and the ocean currents lead to regional variations in the
warming. The Northern Hemisphere has warmed much faster than the Southern
Hemisphere because Northern Hemisphere has much more land, as well as more snow
area and sea ice, Not only that the arrangement of the land masses has effect for this
This anomaly is projected to arise from a weakening of warm northward ocean currents
combined with a shift in the jet stream that will bring colder polar air masses to the