Category: Health - Post Date: Wed 17 Feb, 2016 - Published By: zubair k
Technology ("science of craft", from Greek Ï„Îχνη, techne, "art, skill, cunning of hand"; and -λογία, -logia[3]) is the collection of techniques, skills, methods and processes used in the production of goods or services or in the accomplishment of objectives, such as scientific investigation. Technology can be the knowledge of techniques, processes, etc. or it can be embedded in machines, computers, devices and factories, which can be operated by individuals without detailed knowledge of the workings of such things.
The human species' use of technology began with the conversion of natural resources into simple tools. The prehistoric discovery of how to control fire and the later Neolithic Revolution increased the available sources of food and the invention of the wheel helped humans to travel in and control their environment. Developments in historic times, including the printing press, the telephone, and the Internet, have lessened physical barriers to communication and allowed humans to interact freely on a global scale. The steady progress of military technology has brought weapons of ever-increasing destructive power, from clubs to nuclear weapons.
Global warming and climate change are terms for the observed century-scale rise in the average temperature of the Earth's climate system and its related effects.[2]
Multiple lines of scientific evidence show that the climate system is warming.[3][4][5] Although the increase of near-surface atmospheric temperature is the measure of global warming often reported in the popular press, most of the additional energy stored in the climate system since 1970 has gone into ocean warming. The remainder has melted ice and warmed the continents and atmosphere.[6][a] Many of the observed changes since the 1950s are unprecedented over decades to millennia.[7]
Scientific understanding of global warming is increasing. The Intergovernmental Panel on Climate Change (IPCC) reported in 2014 that scientists were more than 95% certain that global warming is mostly being caused by increasing concentrations of greenhouse gases (GHG) and other human (anthropogenic) activities.[8][9][10] Climate model projections summarized in the report indicated that during the 21st century the global surface temperature is likely to rise a further 0.3 to 1.7 °C (0.5 to 3.1 °F) for their lowest emissions scenario using stringent mitigation and 2.6 to 4.8 °C (4.7 to 8.6 °F) for their highest.[11] These findings have been recognized by the national science academies of the major industrialized nations[12][b] and are not disputed by any scientific body of national or international standing.[14]
Future climate change and associated impacts will differ from region to region around the globe.[15][16] Anticipated effects include warming global temperature, rising sea levels, changing precipitation, and expansion of deserts in the subtropics.[17] Warming is expected to be greater over land than over the oceans and greatest in the Arctic, with the continuing retreat of glaciers, permafrost and sea ice. Other likely changes include more frequent extreme weather events including heat waves, droughts, heavy rainfall with floods and heavy snowfall;[18] ocean acidification; and species extinctions due to shifting temperature regimes. Effects significant to humans include the threat to food security from decreasing crop yields and the abandonment of populated areas due to rising sea levels.[19][20]
