Global warming

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Global mean surface temperatures 1856-2004

Global warming is a slow steady rise in Earth's surface temperature.[1] Temperatures today are 0.74 °C (1.33 °F) higher than 150 years ago.[2] Many scientists say that in the next 100–200 years, temperatures might be up to 6 degrees Celsius higher than they were before the effects of global warming were discovered.

The basic cause seems to be a rise in atmospheric carbon dioxide, as predicted by Svante Arrhenius a hundred years ago. When people use fossil fuels like coal and oil, this adds carbon dioxide to the air. When people cut down the Earth's forests (deforestation), this means less carbon dioxide is taken out of the atmosphere by plants.

If the Earth's temperature becomes hotter the sea level will also become higher. This is partly because water expands when it gets warmer. It is also partly because warm temperatures make glaciers melt. The sea level rise may cause coastal areas to flood. Weather patterns, including where and how much rain or snow there is, will change. Deserts will probably increase in size. Colder areas will warm up faster than warm areas. Strong storms may become more likely and farming may not make as much food. These effects will not be the same everywhere. The changes from one area to another are not well known.

People in government and Intergovernmental Panel on Climate Change (IPCC) have talked about global warming. They do not agree on what to do about it. Some things that could reduce warming are to burn less fossil fuels, adapt to any temperature changes, or try to change the Earth to reduce warming. The Kyoto Protocol tries to reduce pollution from the burning of fossil fuels. Most governments have agreed to it. Some people in government think nothing should change.

Temperature changes[change | change source]

See also: Temperature record of the past 1000 years
A graph of temperatures over the past two thousand years from different proxy reconstructions.

Climate change has happened many times over the history of the Earth, including the coming and going of ice ages. For more recent centuries, we have more details.

Since the 1800s, people have recorded the daily temperature. By about 1850, there were enough places measuring temperature so that scientists could know the global average temperature. From 1920 to 1940, the temperature got warmer. From 1940 to 1970, the temperature got slightly cooler. From 1970 to today, the average temperature for the world has increased by about 0.6 ± 0.2 °C.[3] Starting in 1979, satellites started measuring the temperature of the Earth.

Before 1850, there were not enough temperature measurements for us to know how warm or cold it was. Climatologists use proxy measurements to try to figure out past temperatures before there were thermometers. This means measuring things that change when it gets colder or warmer. One way is to cut into a tree and measure how far apart the growth rings are. Trees that live a long time can give us an idea of how temperature and rain changed while it was alive.

For most of the past 2000 years the temperature didn't change much. There were some times where the temperatures were a little warmer or cooler. One of the most famous warm times was the Medieval Warm Period and one of the most famous cool times was the Little Ice Age. Other proxy measurements like the temperature measured in deep holes mostly agree with the tree rings. Tree rings and bore holes can only help scientists work out the temperature until about 1000 years ago. Ice cores are also used to find out the temperature back to about half a million years ago.

The greenhouse effect[change | change source]

Fossil fuel related CO2 emissions compared to five IPCC scenarios. The dips are related to global recessions.

Coal-burning power plants, car exhausts, factory smokestacks, and other man-made waste gas vents give off about 23 billion tons of carbon dioxide and other greenhouse gases into the Earth's atmosphere each year. The amount of CO2 in the air is about 31% more than it was around 1750. About three-quarters of the CO2 that people have put in the air during the past 20 years are due to burning fossil fuel like coal or oil. The rest mostly comes from changes in how land is used, like cutting down trees.[4]

The Sun[change | change source]

The sun gets a little bit hotter and colder every 11 years. This is called the 11-year sunspot cycle. The change is so small that scientists can barely measure how it affects the temperature of the Earth. If the sun was causing the Earth to warm up, it would warm both the surface and high up in the air. But the air in the upper stratosphere is actually getting colder, so scientists don't think changes in the sun have much effect.

Dust and dirt[change | change source]

Dust and dirt in the air come from natural sources such as volcanos,[5][6] erosion and meteoric dust. People also add to it. Some of this dirt falls out within a few hours. Some is aerosol, so small that it could stay in the air for years.

Some responses[change | change source]

Some people try to stop global warming, usually by burning less fossil fuel. Many people have tried to get countries to emit less greenhouse gases. The Kyoto Protocol was signed in 1997. It was meant to reduce the amount of greenhouse gases in the atmosphere to below their levels in 1990. However, this has not happened. Carbon dioxide levels today are the highest they have been since the start of the Industrial Revolution.

Energy conservation is used to burn less fossil fuel. People can also use energy sources that don't burn fuel, or can prevent the carbon dioxide from getting out.

People can also change how they live because of any changes that global warming will bring. For example, they can go to places where the weather is better, or build walls around cities to keep flood water out. Like the preventive measures, these things cost money, and rich people and rich countries will be able to change more easily than the poor. Geoengineering is also seen by some as one climate change mitigation response.

Etymology[change | change source]

The term global warming was first used in its modern sense on 8 August 1975 in a science paper by Wally Broecker in the journal Science called "Are we on the brink of a pronounced global warming?". Broecker's choice of words was new and represented a significant recognition that the climate was warming; previously the phrasing used by scientists was "inadvertent climate modification," because while it was recognized humans could change the climate, no one was sure which direction it was going. The National Academy of Sciences first used global warming in a 1979 paper called the Charney Report, it said: "if carbon dioxide continues to increase, we find no reason to doubt that climate changes will result and no reason to believe that these changes will be negligible." The report made a distinction between referring to surface temperature changes as global warming, while referring to other changes caused by increased CO2 as climate change.

Global warming became more widely popular after 1988 when NASA climate scientist James Hansen used the term in a testimony to Congress. He said: "global warming has reached a level such that we can ascribe with a high degree of confidence a cause and effect relationship between the greenhouse effect and the observed warming." His testimony was widely reported and afterward global warming was commonly used by the press and in public discourse.

Effects of global warming on sea levels[change | change source]

Global warming means that Antarctica and Greenland ice sheets are melting and the oceans are expanding. Recent climate change would still cause a 6-meter (20-feet) sea-level rise even if greenhouse gas emissions were reduced in 2015 per a scientific paper in Science.[7][8]

Low-lying areas such as Bangladesh, Florida and the Netherlands face massive flooding.[9]

Cities affected by current sea level rise[change | change source]

Places the would be flooded by a 6 meter sea level rise

Many cities under threat of flooding if the present sea level rises.

These and other cities have either started trying to deal with rising sea level and related storm surge, or are discussing this, according to reliable sources.

OECD 2007 report[change | change source]

From a 2007 OECD report;

  1. Miami, USA
  2. Guangzhou, P.R. of China
  3. New York-Newark, USA
  4. Kolkata, India
  5. Shanghai, P.R. of China
  6. Mumbai, India
  7. Tianjin, P.R. of China
  8. Tokyo, Japan
  9. Hong Kong, P.R. of China
  10. Bangkok, Thailand
  11. Ningbo, P.R. of China
  12. New Orleans, USA
  13. Osaka-Kobe, Japan
  14. Amsterdam, The Netherlands
  15. Rotterdam, The Netherlands
  16. Ho Chi Minh City, Vietnam
  17. Nagoya, Japan
  18. Qingdao, China
  19. Virginia Beach, USA
  20. Alexandria, Egypt

Another seven cities that are exposed to coastal flooding:

  • Rangoon, Myanmar
  • Hai Phòng, Vietnam
  • Khulna, Bangladesh
  • Lagos, Nigeria
  • Abidjan, Cote D'Ivoire
  • Chittagong, Bangladesh
  • Jakarta, Indonesia

Further reading[change | change source]

Related pages[change | change source]

References[change | change source]

  1. Campbell, Neil A. 2009. Biology concepts & connections; page 119. Retrieved 2010-07-21.
  2. IPCC (2007). "Summary for policymakers" (PDF). Climate change 2007: The physical science basis: Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Retrieved 2009-07-03.
  3. "Climate change 2001: the scientific basis". UNEP/GRID-Arendal ( Retrieved 2010-11-03. en:UNEP/GRID-Arendal
  4. "Climate change 2001: the scientific basis". Retrieved 2010-11-03.
  5. Sun-dimming Volcanoes Partly Explain Global Warming Hiatus Feb 23, 2014 Reuters via Scientific American
  6. Volcanoes that act as air-conditioning for a warming world; Many small eruptions over the past decade or so have helped restrain climate change May 2014 issue Scientific American
  7. John von Radowitz (July 13, 2015). "Rising oceans impact ‘enormous’". Times of Malta. Retrieved 24 October 2015.
  8. Dutton, A.; A. E. Carlson, A. J. Long, G. A. Milne, P. U. Clark, R. DeConto, B. P. Horton, S. Rahmstorf, M. E. Raymo (10 July 2015). "Sea-level rise due to polar ice-sheet mass loss during past warm periods". Science (journal) 349 (6244). DOI: 10.1126/science.aaa4019. Retrieved 24 October 2015.
  9. Scientists to issue stark warning over dramatic new sea level figures
  10. Floods in London. [1] Royal Geographical Society
  11. en:PlaNYC
  12. Sea Level Rise; Projections and Impacts for New York
  13. interactive map from Climate Central
  14. Sea Level Rise Tool for Sandy Recovery en:U.S. Global Change Research Program
  15. World Bank, World Development Report 2010, 91.
  16. en:Climate change in New York City
  17. Noguchi, Yuki (2014-06-24). "As Sea Levels Rise, Norfolk Is Sinking And Planning". NPR. Retrieved 2014-11-25.
  18. National Security and the Accelerating Risks of Climate Change May 2014 CNA Military Advisory Board
  19. Investigation of Air Pollution Standing Conference
  20. Montgomery, David (2013-10-24). "Crisfield, Md., beats back a rising Chesapeake Bay". Washington Post. Retrieved 2013-10-27.
  21. Two cities, two very different responses to rising sea levels July 2, 2015 PBS NewsHour
  22. Jeff Goodell (June 20, 2013). "Goodbye, Miami". Rolling Stone. Retrieved June 21, 2013. "The Organization for Economic Co-operation and Development lists Miami as the number-one most vulnerable city worldwide in terms of property damage, with more than $416 billion in assets at risk to storm-related flooding and sea-level rise."
  23. Climate Change Economics February 2015 National Geographic
  25. Most at risk: Study reveals Sydney's climate change 'hotspots' - ABC News (Australian Broadcasting Corporation)
  27. Khan, Sami (2012-01-25). "Effects of Climate Change on Thatta and Badin". Retrieved 2013-10-27.
  28. World Bank, World Development Report 2010, 91.

Other websites[change | change source]

Find more information on climate change by searching one of Wikipedia's sister projects:

Wiktionary-logo-en.svg Dictionary definitions from Wiktionary
Wikibooks-logo.svg Textbooks from Wikibooks
Wikiquote-logo.svg Quotations from Wikiquote
Wikisource-logo.svg Source texts from Wikisource
Commons-logo.svg Images and media from Commons
Wikinews-logo.svg News stories from Wikinews
Wikiversity-logo-en.svg Images and media from Wikiversity
Wikispecies-logo.svg Images and media from Wikispecies
Wikidata-logo.svg Database entry from Wikidata
MediaWiki-notext.svg Documentation from MediaWiki

Public administrations and organizations[change | change source]

Other links[change | change source]

BBC articles[change | change source]