The Definition of Climate change by UNFCCC
“Climate change” means a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods.
Cause of Climate Change
Demand for energy and associated services, to meet social and economic development and improve human welfare and health, is increasing. All societies require energy services to meet basic human needs (e.g., lighting, cooking, space comfort, mobility and communication) and to serve productive processes. Since approximately 1850, global use of fossil fuels (coal, oil and gas) has increased to dominate energy supply, leading to rapid growth in carbon dioxide (CO2) emissions.
Green house gas (GHG) emissions resulting from the provision of energy services have contributed significantly to historic increase in atmospheric GHG concentrations. The IPCC Fourth Assessment Report (AR4) concluded that “Most of the observed increase in global average temperature since the mod-20th century is very likely due to the observed increase in anthropogenic gas concentrations.”
Recent data confirm that consumption of fossil fuels accounts for the majority of global anthropogenic GHG emissions.3 Emissions continue to grow and CO2 concentrations had increased to 390 ppm, or 39% above pre-industrial levels, by the end of 2010.
GHG emissions associated with the provision of energy services are a major cause of climate change. The AR4 concluded that “Most of the observed increase in global average temperature since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.” (IPCC,2007a). Concentration of CO2 have continued to grow since the IPCC Fourth Assessment Report (AR4) to about 390 ppm CO2 or 39% above pre-industrial levels by the end of 2010 (IPCC, 2007b; NOAA,2010). The global average the temperature has increased by 0.76 ͦ C (0.57 ͦ C to 0.95 ͦ C) between 1850 to 1899 and 2001 to 2005, and the warming trend has increased significantly over the last 50 years (IPCC,2007b). While this report focuses on the energy sector, forest clearing and burning and land use change, and the release of non-CO2 gases from industry, commerce and agriculture also contribute to global warming (IPCC, 2007b).
Reference : The Special Report on Renewable Energy Sources and Climate Change Mitigation (SRREN), agreed and released by the Intergovernmental Panel on Climate Change (IPCC) on May 9th in Abu Dhabi
Full Report Download: http://srren.ipcc-wg3.de/report/IPCC_SRREN_Full_Report.pdf