Directory : Water Directory 2014
WATER DIRECTORY 2014 AUSTRALIAN WATER INFORMATION AND STATISTICS 5th IPCC Assessment Report: Summary of Draft Report The Intergovernmental Panel on Climate Change (IPCC) was established by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP) to assess scienti c, technical and socio-economic information concerning climate change, its potential effects and options for adaptation and mitigation. In 1990, the date of the rst IPCC report, the scienti c advice on collected observations drew attention to a global warming trend. Since then, three subsequent reports and contributions from an ever- widening group of scientists across the globe have provided evidence from monitoring of changes to global temperatures on land, sea and air, atmospheric gas composition, glaciers and ice cover, sea salinity and pH, and the frequency and severity of weather events that a warming trend is continuing and climate change is real. Scientists report that not only is the climate changing, but also that its behaviour is complex and not fully understood. In the distant past, cataclysmic events on earth triggered major changes to the climate and the conditions for life to survive. These events included periods of intense geological activity (such as earthquakes and volcanic eruptions) followed by a series of Ice Ages, the formation of continents, the supercontinents Pangaea, Gondwanaland and the Age of the Dinosaurs, interspersed with quieter periods of recovery when the conditions developed to make life possible until the arrival of the next major catastrophe. Now, years hence, the extent to which humans and their behaviours are in uencing the speed, form and extent of environmental change for earth is the key question that preoccupies climate scientists. The panels of scientists that contribute to the most recent IPCC assessment report, its fth since 1990, provide extensive and complex data on what are believed to be major indicators of a changing climate -- the contribution and behaviour of gases in the atmosphere, sea level changes, the thickness and extent of polar ice sheets, global temperature changes, the rate of glacial melt and more. The 5th IPCC Assessment Report draws conclusions from the collated data to focus on the human contribution to component parameters and the changes to attribute them principally to human behaviour -- most speci cally activities that increase the level of carbon dioxide and related greenhouse gases in the atmosphere. Historical data contained in Table SPM.1 of the IPCC 5AR Summary Report Draft dated 27 September 2013 states that: • It is likely (with medium con dence) that 1983--2013 was the warmest 30-year period for 1400 years. • It is virtually certain the upper ocean warmed from 1971 to 2010. This ocean warming accounts, with high con dence, for 90% of the energy accumulation between 1971 and 2010. • It can be said with high con dence that the Greenland and Antarctic ice sheets have been losing mass in the last two decades and that Arctic sea ice and Northern Hemisphere spring snow cover have continued to decrease in extent. • There is high con dence that the sea level rise since the middle of the 19th century has been larger than the mean sea level rise of the prior two millennia. • Concentration of greenhouse gases in the atmosphere has increased to levels unprecedented on earth in 800,000 years. • Total radiative forcing of the earth system, relative to 1750, is positive and the most signi cant driver is the increase in CO2's atmospheric concentration.
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