Over the last hundred years or so, many significant changes in the climate have been recorded, which shows a trend of rising global mean temperature, i. e. global warming, rising sea levels, Arctic shrinkage, Arctic methane release, emission of global carbon from permafrost areas, and Arctic methane release in coastal residues. Global warming is dangerous for our environment and our lives also. Global average temperature is expected to rise over this century, resulting in unpredictable extreme weather changes. Some of the substantial effects of climate change are irretrievable at continental and global scales.
It is estimated that the sea level will rise 18 to 59 cm (7.1 to 23.2 inches) by the end of the 21st century. This estimation is done without considering the probable additions by the melting of ice sheets. Even a global warming of 1-4 degree C (comparative to 1990-2000) can cause a partial deglaciation of the Greenland ice sheet and the West Antarctic ice sheet that would raise the sea level by 4-6 m or more. Meridional Overturning Circulation is expected to slow down in this century, whereas the temperature in the Atlantic and Europe will perhaps still be higher because of global warming. Some regions will be drowned forever if the sea level rises a little more.
Global warming may affect the human system very badly in many ways, but the impacts may vary from region to region. Some areas may be benefitted while the others may be badly affected. But if the temperature rises more than 2-3 degree C, the benefits will be overshadowed by the losses. Low-latitude and less-developed regions are prone to more sufferings. Though the human system has the potential to adapt to climate changes, nobody can surely predict the extent and capability of adaptation, and at what cost. Diversity of ecology would be reduced and many species will extinct forever. Biological and geophysical systems have less potential for adaptability in comparison with human systems. Consequences of global warming are alarming and must be tackled timely.