Environmentalism is a broad philosophy and social movement regarding concerns for environmental conservation and improvement of the state of the environment. Environmentalism and environmental concerns are often represented by the color green.
- 1 Environmentalism as a social movement
- 2 History
- 2.1 Origins of the modern environmental movement
- 3 Environmental movement
- 4 Free market environmentalism
- 5 Evangelical environmentalism
- 6 Preservation and conservation
- 7 Environmental organizations and conferences
- 8 Criticisms
- 9 See also
- 10 References
- 11 Further reading
- 12 External links
Environmentalism as a social movement
Environmentalism can also be seen as a social movement that seeks to influence the political process by lobbying, activism, and education in order to protect natural resources and ecosystems. An environmentalist is a person who may speak out about our natural environment and the sustainable management of its resources through changes in public policy or individual behavior by supporting practices such as not being wasteful. In various ways (for example, grassroots activism and protests), environmentalists and environmental organizations seek to give the natural world a stronger voice in human affairs. Continue reading
Global warming is the increase in the average temperature of Earth’s near-surface air and oceans since the mid-20th century and its projected continuation. According to the 2007 Fourth Assessment Report by the Intergovernmental Panel on Climate Change (IPCC), global surface temperature increased 0.74 ± 0.18 °C (1.33 ± 0.32 °F) during the 20th century.[A] Most of the observed temperature increase since the middle of the 20th century has been caused by increasing concentrations of greenhouse gases, which result from human activity such as the burning of fossil fuel and deforestation. Global dimming, a result of increasing concentrations of atmospheric aerosols that block sunlight from reaching the surface, has partially countered the effects of warming induced by greenhouse gases.
Climate model projections summarized in the latest IPCC report indicate that the global surfacetemperature is likely to rise a further 1.1 to 6.4 °C (2.0 to 11.5 °F) during the 21st century. The uncertainty in this estimate arises from the use of models with differing sensitivity to greenhouse gas concentrations and the use of differing estimates of future greenhouse gas emissions. An increase in global temperature will cause sea levels to rise and will change the amount and pattern of precipitation, probably including expansion of subtropical deserts. Warming is expected to be strongest in the Arctic and would be associated with continuing retreat of glaciers,permafrost and sea ice. Other likely effects include changes in the frequency and intensity ofextreme weather events, species extinctions, and changes in agricultural yields. Warming and related changes will vary from region to region around the globe, though the nature of these regional variations is uncertain. As a result of contemporary increases in atmospheric carbon dioxide, the oceans have become more acidic, a result that is predicted to continue.
The scientific consensus is that anthropogenic global warming is occurring.[B]Nevertheless, political and public debate continues. The Kyoto Protocol is aimed at stabilizing greenhouse gas concentration to prevent a “dangerous anthropogenic interference”. As of November 2009, 187 states had signed and ratified the protocol.
Proposed responses to climate change include mitigation to reduce emissions, adaptation to the effects of global warming, and geoengineering to remove greenhouse gases from the atmosphere or block incoming sunlight.
- 1 Temperature changes
- 2 External forcings
- 2.1 Greenhouse gases
- 2.2 Aerosols and soot
- 2.3 Solar variation
- 3 Feedback
- 4 Climate models
- 5 Attributed and expected effects
- 5.1 Natural systems
- 5.2 Ecological systems
- 5.3 Social systems
- 6 Responses to global warming
- 6.1 Mitigation
- 6.2 Adaptation
- 6.3 Geoengineering
- 6.4 UNFCCC
- 7 Views on global warming
- 7.1 Politics
- 7.2 Public opinion
- 7.3 Other views
- 8 Etymology
- 9 See also
- 10 Notes
- 11 References
- 12 Further reading
- 13 External links
Main article: Temperature record
Two millennia of mean surface temperatures according to different reconstructions, each smoothed on a decadal scale, with the actual recorded temperatures overlaid in black.
Evidence for warming of the climate system includes observed increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level. The most common measure of global warming is the trend in globally averaged temperature near the Earth’s surface. Expressed as a linear trend, this temperature rose by 0.74 ± 0.18 °C over the period 1906–2005. The rate of warming over the last half of that period was almost double that for the period as a whole (0.13 ± 0.03 °C per decade, versus 0.07 °C ± 0.02 °C per decade). The urban heat island effect is estimated to account for about 0.002 °C of warming per decade since 1900. Temperatures in the lower troposphere have increased between 0.13 and 0.22 °C (0.22 and 0.4 °F) per decade since 1979, according to satellite temperature measurements. Temperature is believed to have been relatively stable over the one or two thousand years before 1850, with regionally varying fluctuations such as the Medieval Warm Period and the Little Ice Age. Continue reading
Climate change is a long-term change in the statistical distribution of weather patterns over periods of time that range from decades to millions of years. It may be a change in the average weather conditions or a change in the distribution of weather events with respect to an average, for example, greater or fewer extreme weather events. Climate change may be limited to a specific region, or may occur across the whole Earth.
In recent usage, especially in the context of environmental policy, climate change usually refers to changes in modern climate. It may be qualified as anthropogenic climate change, more generally known as global warming or anthropogenic global warming (AGW).
- 1 Terminology
- 2 Causes
- 2.1 Plate tectonics
- 2.2 Solar output
- 2.3 Orbital variations
- 2.4 Volcanism
- 2.5 Ocean variability
- 2.6 Human influences
- 3 Physical evidence for climatic change
- 3.1 Historical and archaeological evidence
- 3.2 Glaciers
- 3.3 Vegetation
- 3.4 Ice cores
- 3.5 Dendroclimatology
- 3.6 Pollen analysis
- 3.7 Insects
- 3.8 Sea level change
- 4 See also
- 5 References
- 6 Further reading
- 7 External links
The most general definition of climate change is a change in the statistical properties of the climate system when considered over periods of decades or longer, regardless of cause. Accordingly, fluctuations on periods shorter than a few decades, such as El Niño, do not represent climate change.
The term sometimes is used to refer specifically to climate change caused by human activity; for example, the United Nations Framework Convention on Climate Change defines climate change as “a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods.” In the latter sense climate change is synonymous with global warming.
Factors that can shape climate are climate forcings. These include such processes as variations in solar radiation, deviations in the Earth’sorbit, mountain-building and continental drift, and changes in greenhouse gas concentrations. There are a variety of climate change feedbacksthat can either amplify or diminish the initial forcing. Some parts of the climate system, such as the oceans and ice caps, respond slowly in reaction to climate forcing because of their large mass. Therefore, the climate system can take centuries or longer to fully respond to new external forcings. Continue reading
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