Global warming in common words is rise in temperature of earth. It leads to warming up of whole world or globe. It damages the layer of O³ which is ozone layer.
A common view is that current global warming rate will continue or accelerate.
But we argue that rapid warming in recent decades has been driven mainly by non-CO2 greenhouse gases (GHS), such as chlorofluorocarbons, CH4, and N2O, not by the products of fossil fuel burning, CO2 and aerosols, the positive and negative climate forcing of which are partially offsetting.
The growth rate of non-CO2 GHS has declined in the past decade. If sources of CH4 and O3 precursors were reduced in the future, the change in climate forcing by non-CO2 GHS in the next 50 years could be near zero. Combined with a reduction of black carbon emissions and plausible success in slowing CO2 emissions, this reduction of non-CO2 GHS could lead to a decline in the rate of global warming, reducing the danger of dramatic climate change.
Such focus on air pollution has practical benefits that unite the interests of developed and developing countries. However, the assessment of ongoing and future climate change requires composition-specific long-term global monitoring of aerosol properties.
The global surface temperature has increased by about 0.5 °C since 1975 (1, 2), a burst of warming that has taken the global temperature to its highest level in the past millennium (3). There is a growing consensus (4) that the warming is at least in part a consequence of increasing anthropogenic greenhouse gases (GHS).
GHS cause a global climate forcing, ex an imposed perturbation of Earth's energy balance with space (5). There are many competing natural and anthropogenic climate forcing, but increasing GHG are estimated to be the largest forcing and to result in a net positive forcing, especially during the past few decades (4, 6). Evidence which supports this interpretation is provided by observed heat storage in the ocean (7), which is positive and of the magnitude of the energy imbalance estimated from climate forcing for recent decades (8).
The Intergovernmental Panel on Climate Change (IPCC) (4) has considered a range of scenarios for future GHS, which is further expanded in its Special Report on Emissions Scenarios (9).
Yet global warming simulations have focused on “business as usual” scenarios with rapidly increasing GHS. These scenarios yield a steep, relentless increase in global temperature throughout the twenty-first century (4, 10) with warming of several degrees Celsius by 2100, if climate sensitivity is 2–4 °C for doubled CO2, as climate models suggest (4, 11–13). These figures can also give the impression that curtailment of global warming is almost hopeless.
The 1997 Kyoto Protocol, which calls for industrialized nations to reduce their CO2 emissions to 95% of 1990 levels by 2012 (14), is itself considered a difficult target to achieve. Yet the climate simulations lead to the conclusion that the Kyoto, reductions will have little effect in the twenty-first century (15), and 30 Kyoto may be needed to reduce global to an acceptable level.
It has been increasing since some previous years and it very big danger for living beings if nothing is done in concern about it.
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