Global warming
From Wikipedia, a free encyclopedia written in simple English for easy reading.
Global warming is the name given to the idea that the world's air has become hotter over the last two hundred years. It is also used as the name of this event. (An event is something that happens.) Some people say that global warming is a very serious problem for the world, that it causes floods and storms for example. Others say that there is nothing for the world to worry about.
Today, the atmosphere of the world is about a half a degree Celsius (something you measure temperature in) hotter than it was two hundred years ago. But many people disagree about whether this is caused by man's pollution (from cars and factories for example), or a natural change.
The average temperature at the surface of the Earth has gone up by 0.6°C since the late 19th century[1]. This is known as Global warming. There are several theories which try and explain this increase. Most of the warming of the last 50 years is believed to be a result of increases in the greenhouse effect caused by human-generated carbon dioxide (CO2); variations in the amount of heat from the sun and other natural causes also play a role.
Climate models predict that temperatures will increase by 1.4°C - 5.8°C between 1990 and 2100 [2]. Much of the uncertainty in this increase results from not knowing future CO2 emissions, but there is also uncertainty about the accuracy of climate models. Climate commitment studies predict that even if levels of greenhouse gases and solar activity were to remain constant, the global temperature will increase by 0.5°C over the next one hundred years due to the lag in warming caused by the oceans.
Although the discussion of global warming often focuses on temperature, global warming or any climate change[3] may cause changes in other things as well, including the sea level, precipitation, weather patterns, etc. These may affect human activity via floods, droughts, heat waves, changes to agricultural yields, etc.
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[edit] Is the globe warming?
The average temperature should be raised by 2 degreees every 10 years
Over the past century or so the global (land and sea) temperature has increased by approximately 0.6 ± 0.2°C [4]. Over the past 1-2 thousand years the temperature has been relatively stable, with various (possibly local) fluctuations, such as the Medieval Warm Period or the Little Ice Age.
For details of changes during various periods:
- General discussion of Temperature records see: Temperature record
- Record of past century see: Instrumental temperature record
- Record of recent millennia see: Temperature record of the past 1000 years
- For attribution see: Anthropogenic climate change
- For the temperature of the lower troposphere since 1979, see Satellite temperature measurements
[edit] Why is the world warming?
[edit] Greenhouse gases have increased...
Coal-burning power plants, automobile exhausts, factory smokestacks, and other waste vents of the human environment contribute about 22 billion tons of carbon dioxide and other greenhouse gases into the earth's atmosphere each year. The atmospheric concentration of CO2 has increased by 31% above pre-industrial levels since 1750. This is considerably higher than at any time during the last 420,000 years, the period for which reliable data has been extracted from ice cores. From less direct geological evidence it is believed that CO2 values this high were last attained 40 million years ago. About three-quarters of the anthropogenic emissions of CO2 to the atmosphere during the past 20 years is due to fossil fuel burning. The rest is predominantly due to land-use change, especially deforestation [5].
[edit] But there may be other factors
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Theory(a guess) says that greenhouse gas(trapped gas) increases should warm the planet; the problem is knowing by exactly how much they should have affected temperature in the past and in the future. Climate models are used to try to answer these questions. These models do not clearly relate the warming that occurred from approximately 1910 to 1945 to either natural variation or human effects; however, they suggest that the warming since 1975 is dominated by man-made greenhouse gas emissions. The opinion of the much of the world's climatologists (people who study the weather) is that recent warming is due to human influence, via greenhouse gas emissions.
Many hypotheses have been proposed to attribute terrestrial temperature variations to variations in solar output/Solar variation theory. In the IPCC TAR, it was reported that volcanic and solar forcings might account for half of the temperature variations prior to 1950, but that the net effect of such natural forcings was roughly neutral since then [6].
Various other hypotheses have been proposed, including but not limited to:
- The warming is within the range of natural variation and needs no particular explanation
- The warming is a consequence of coming out of a prior cool period — the Little Ice Age — and needs no other explanation
- The warming trend itself has not been clearly established, and therefore does not need any explanation. See also urban heat island.
[edit] Future
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If the theory is correct then the attribution of past change constrains the model sensitivity to some extent and permits prediction of future change, based on assumptions about future emissions. Climate models, forced by GHG etc, project a warming of 1.4°C to 5.8°C between 1990 and 2100 [7]. If the dominant GHG theory is substantially wrong and solar forcing is more important than realised, then future prediction is not currently possible because forecasts of future solar variability are too uncertain.
[edit] Potential effects
The effects of global warming are not agreed on very well by people. Some believe that this is very important and needs attention, but others believe that this is not a major issue. Scientists are trying to figure it out, but nobody is completely sure about the effects.
[edit] Attempts to combat global warming
[edit] Slowing temperature rise
- Kyoto Protocol
- Carbon sequestration / Carbon tax
- Future energy development
- Soft energy path
- United Kingdom Climate Change Programme
- Solar Panels
- Congestion Charge in the city of London
- Improving Londons Public Transports
- Trams
- Economical Cars
- Extra tax for larger Engines
- Energy Efficiant Products
[edit] Slowing the effects of global warming
- Impact of global climate changes on agriculture
- flood defence
[edit] See also
Global warming relates to a number of other issues which are discussed elsewhere:
- ozone depletion
- global dimming
- sea level rise
- Global warming controversy
- scientific opinion on climate change
[edit] Notes
- ^ Use of the term "global warming" generally implies a human influence — the more neutral term climate change is usually used for a change in climate with no presumption as to cause and no characterization of the kind of change involved, such as the Ice Ages. Note, however, that there is one important exception to this: the UNFCCC uses "climate change" for human caused change and "climate variability" for non-human caused change [8]. Sometimes the term "anthropogenic climate change" is used to indicate the presumption of human influence.
[edit] External links
[edit] Data
- NOAA CMDL CCGG - Interactive Atmospheric Data Visualization NOAA CO2 data
- UNEP - The present carbon cycle - Climate Change carbon levels and flows
- Temperature data Climatic Research Unit, University of East Anglia, Norwich, UK. Philip D. Jones and other.
- Hadley Centre: Global temperature data
[edit] Carbon dioxide "production"
- International Energy Annual: Reserves
- IEA Publications Bookshop - Key World Energy Statistics
- International Energy Annual 2002: Carbon Dioxide Emissions
[edit] Scientific
- NASA's Global Hydrology and Climate Center
- NASA's Goddard Institute for Space Studies (GISS) — Global Temperature Trends.
- NASA's GISS paleoclimate site
- National Oceanic and Atmospheric Administration — NOAA, United States Department of Commerce — Global Warming FAQ
- NOAA's paleoclimate site
- MIT Joint Program on the Science and Policy of Global Change
- Real climate a blog where scientists discuss the science of global warming
[edit] Educational
- New Scientist: Climate Change — Latest news, articles and FAQ on climate change from New Scientist magazine.
- Discovery of Global Warming — An extensive introduction to the topic and the history of its discovery
- Science of Climate Change — Meteorological Service of Canada, a guide to understanding the science behind climate change with a thorough FAQ section.
- Global warming - a briefing document, summarising current arguments concerning global warming. They present various points of view and some of the basic problems in following the science.
[edit] Other
- A large compendium of links to sites with information on global warming
- Ross McKitrick's commented list of resources on global warming
- Science and Technology Librarianship: Global Warming and Climate Change Science — Extensive commented list of Internet resources — Science and Technology Sources on the Internet.
- Activist Magazine: Carbon Activism for Beginners
- Stop Climate Chaos ~ ACT for the Earth
