Increased carbon emissions since 1850 1 (have resulted) in higher percentages of CO2 in the atmosphere, which is 2 (causing / ) global warming. The forest fires in Asia, Europe and the USA in 2007 3 (caused/) a further increase in carbon emissions. 4 / As) atmospheric temperatures rise, this is causing the ice at the poles to melt much faster. 5 (As / ) meltwater runs down to the base of the icecaps, parts of them slip and fall into the sea as icebergs. In addition, pools of water form on the surfaces of the icecaps. 6 (Since / ) this makes the ice darker, it absorbs more heat. This is already happening in Greenland and West Antarctica. 7 ( As a result) of these changes, the icecaps will melt faster than expected. The rising sea level will 8 (/ result) in the submergence and disappearance of many of the world’s most crowded cities. In addition, reduced icecaps could 9 (cause / ) much higher rises in global temperatures, 10 / because) less heat from the sun is reflected back into space from the ice. About 3.5 million years ago, temperatures increased to 2-3 degrees above today’s level. 11 (As a result /), sea levels rose by 25 meters. So, how can we reduce carbon emissions? One study recommends linking the electricity networks of Europe, North Africa and Iceland with high voltage DC cables. This would provide a greater choice of renewable power. 12 (As a result /), every country in the network would be able to use hydroelectricity from Scandinavia and geothermal power from Iceland.