The climate varies continuously, but according to climate scientists, it is now changing with unprecedented rate. Since the end of the 19th century, the mean global temperature has increased from 0.3 to 0.60C. In addition, the global sea level has risen from 10 to 25 cm. Regional changes in temperature and precipitations are also evident. Evidence suggests there is a discernible human influence on the global climate. This conclusion was drawn by the Intergovernmental Panel on Climate change (IPCC, 2007 and 2014). The IPCC was established in 1988 by two United Nations Organisations, the World Meteorological Organisation (WMO) and the United Nations Environment Programme (UNEP) to assess available scientific information on climate change, to estimate the environmental and socio-economic impact of climate change, and to formulate response strategies. The assessment reports of the IPCC are written and reviewed by prominent scientists and other experts from all over the world. They are considered standard works of reference.
According to the IPCC (2007) , the composition of the earth‘s atmosphere is changing due to human activities. Atmospheric concentrations of greenhouse gases have grown significantly. These gases tend to have a warming effect by absorbing infrared
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radiation from the earth‘s surface and then re-radiating it. Atmospheric concentrations of aerosols have generally grown as well. Aerosols are microscopic airborne particles that, on balance, tend to have a cooling effect. Although locally, the cooling effect due to aerosols may be large enough to offset the warming effect due to greenhouse gases, this does not hold globally. Taking into account the effects of greenhouse gases and aerosols, human interference is projected to increase the mean temperature on earth.
Nations from all over the world are taking counsel together on how to ameliorate climate change.
The third Conference of the Parties in Kyoto has resulted in new agreements between industrialized nations to decrease their emissions of greenhouse gases (CoP 3, 1997).
The Netherlands agreed to reduce aggregate anthropogenic carbon dioxide (CO2) equivalent emissions of greenhouse gases by at least 8 per cent below 1990 levels.
This reduction should be realised between 2008 and 2012 and maintained thereafter.World Summit on Sustainable Development(WSSD) Johannesburg (2002),held a meeting to review progress on sustainable development made since the landmark 1992 Earth Summit held in Rio de Janeiro, Brazil. The WSSD was attended by more than 110 heads of state, as well as over 50,000 delegates and members of non-governmental organisations (NGOs) to emphasise largely on ―New development models towards sustainable development‖. The Bali Action Plan (BAP) adopted in 2007 at COP-13 in Bali, was a continuation of the global action against climate change. It significantly identified the building blocks required for a strengthened future response to climate change, in preparation for the Copenhagen Conference in 2009. The whole world had hoped that Copenhagen (COP) of 2009 was going to produce a turnaround in climate change negotiation in such a way as to create a definite future for the earth‘s climates. The 17th Conference of the Parties (COP-17) and the 17th meeting of the parties to the Kyoto Protocol (COP/MOP -7) in Durban in December 2011 provided, a very crucial opportunity for the whole world to negotiate a second commitment period for the Kyoto Protocol, which expires in 2012.It is geared towards the sustenance of global actions to reduce the emission of greenhouse gases, which are known to be responsible for global warming and climate change.
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As appears from the expression of reduction targets in CO2equivalents, one of the most important anthropogenic greenhouse gases is CO2(Fransen and Janssen, 1998).
Emissions of CO2are mainly due to the combustion of fossil fuels for the generation of energy. The global demand for fossil fuels has grown for almost two centuries and is expected to continue to grow at least through the first half of the next century.
Unless measures are taken, this means atmospheric concentrations of CO2 will also continue to grow. Significant reductions in CO2 emissions can be achieved by replacing current technology with more energy efficient technology and by switching to low-carbon fossil fuels and non-fossil fuels. In the longer term, renewable energy sources such as solar, wind and biomass technologies could meet a considerable part of the world‘s energy demand.
Climate change is a global problem which affects everyone, but not equally (Rana, 2007). Geographic location is a key factor; some areas are simply more affected than others through their physical characteristics and the interaction between local climate systems. The IPCC 2007 report that ‗the list of hottest years on record is dominated by years from This millennium, each of the last 12 years (2001-2012) features as one of the 14 warmest years in the instrumental record of global surface temperature (since 1850). Warming is most pronounced in higher northern latitudes, and land areas have warmed faster than oceans. There is evidence that the significant increases in precipitation observed in eastern parts of North and South America, northern Europe as well as northern and central Asia, and the declines in the Sahel, the Mediterranean, southern Africa and parts of southern Asia over the last century have been exacerbated by anthropogenic climate change. Anthropogenic climate change is more likely than not responsible for the increase in areas affected by drought in the last 40 years. These trends are likely to continue and it is very likely that hot extremes, heat waves and heavy precipitation events will become more frequent.
Earth‘s average temperature has risen to about 1 degree Centigrade in the past 100 years and is projected to rise another 3 to 10 degrees Centigrade in the next 100 years.
While Earth‘s climate has changed naturally over time, the current rate of change due to human activity is unprecedented. The projected range of temperature rise is wide because it includes a variety of possible future conditions, such as whether or not we
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control greenhouse gases emissions and different ways the climate system might respond. Temperatures over the US are expected to rise more than over the globe as a whole because land areas close to the poles are projected to warm faster than those nearer the equator.
Climate change is expected to increase the frequency and intensity of severe weather events. Poor countries lack the infrastructure necessary (e.g. storm walls, water storage) to respond adequately to such events. Diseases such as malaria are likely to have wider ranges, impacting more people in the poorest regions of developing nations that are already most affected by such diseases. Changing rainfall patterns could devastate rain-fed agriculture on which so much of the populations in developing countries depend to survive. In Africa, for example, only 4% of all cropped land is irrigated (Adelekan and Gbadegesin, 2004; Oladipo, 2012).
There is scientific consensus that global warming is real, is caused by human activities, and presents serious challenges. Scientists working on this issue report that the observed global warming cannot be explained by natural variations such as changes in the sun‘s output or volcanic eruptions. The most authoritative source of information is the IPCC 2007, 2009, 2011, 2012, 2013 and 2014 which draws upon the collective wisdom of many hundreds of scientists from around the world. The IPCC projects global temperature increases of 3 to 10 degrees Centigrade in the next 100 years and states that human activity is the cause of most of the observed and projected warming.
Each of us can reduce our contribution to global warming by using less greenhouse gases producing energy: driving less, choosing fuel efficient cars and appliances (like refrigerators and water heaters), and using solar energy where feasible for water and space heat. We can encourage our political and business leaders to institute policies that will save energy and develop alternative energy sources that do not release carbon dioxide. We can preserve existing forests and plant new ones. But even if we take aggressive action now, we cannot completely prevent climate change because once carbon dioxide is in the atmosphere, it remains there for about a century, and the climate system takes a long time to respond to changes. But our actions now and in the coming decades will have enormous implications for future generations.
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