About
Throughout its long history,earth has warmed and cooled time and again.Climate has changed when the planet received more or less sunlight due to subtle shifts in its orbit,as the atmosphere or surface changed,or when the Sun’s energy varied.But in the past century, another force has started toinfluence Earth’s climate-humanity.
Global warming is the unusually rapid increase in Earth’s average surface temperature over the past century primarily due to the greenhouse gases released by people burning fossil fuels.Earth has experienced climate change in the past without help from humanity.But the current climatic warming is occurring muchmore rapidly than past warming events.
In Earth’s historybefore the Industrial Revolution,Earth’s climate changed due to natural causes unrelated to human activity.These natural causes are still in play today,but their influence is too small or they occur too slowly to explain the rapid warming seen in recent decades.
Global warming is the unusually rapid increase in Earth’s average surface temperature over the past century primarily due to the greenhouse gases released by people burning fossil fuels.Earth has experienced climate change in the past without help from humanity.But the current climatic warming is occurring muchmore rapidly than past warming events.
In Earth’s historybefore the Industrial Revolution,Earth’s climate changed due to natural causes unrelated to human activity.These natural causes are still in play today,but their influence is too small or they occur too slowly to explain the rapid warming seen in recent decades.
Greenhouse Gas Overview
Gases that trap heat in the atmosphere are often called greenhouse gases.Some greenhouse gasessuch as carbon dioxide occur naturally and are emitted to the atmosphere through natural processes and human activities. Other greenhouse gases (e.g., fluorinated gases) are created and emitted solely through human activities.The principal greenhouse gases that enter the atmosphere because of human activities are:
- Carbon dioxide(co2):Carbon dioxide enters the atmosphere through the burning of fossil fuels (oil, natural gas, and coal),solid waste,trees and wood products,and also as a result of other chemical reactions (e.g., manufacture of cement).Carbon dioxide is also removed from the atmosphere (or “sequestered”) when it is absorbed by plants as part of the biological carbon cycle.
- Methane (CH4):Methane is emitted during the production and transport of coal,natural gas,and oil.Methane emissions also result from livestock and other agricultural practices and by the decay of organic waste in municipal solid waste landfills.
- Nitrous Oxide (N2O):Nitrous oxide is emitted during agricultural and industrial activities, as well as during combustion of fossil fuels and solid waste.
- Fluorinated Gases: Hydrofluorocarbons,perfluorocarbons,and sulfur hexafluoride are synthetic,powerful greenhouse gases that are emitted from a variety of industrial processes.Fluorinated gases are sometimes used as substitutes for ozone-depleting substances (i.e., CFCs, HCFCs, and halons).These gases are typically emitted in smaller quantities,but because they are potent greenhouse gases,they are sometimes referred to as High Global Warming Potential gases (“High GWP gases”).
How Will Earth Respond to Warming Temperatures?
The impact of global warming is far greater than just increasing temperatures.Warming modifies rainfall patterns,amplifies coastal erosion,lengthens the growing season in some regions, melts ice caps and glaciers,and alters the ranges of some infectious diseases.Some of these changes are already occurring.
World will not meet 2C warming target, climate change experts agree
The gold standard of global warming (despite its inadequacies relative to the assessment of trends in the ocean heat content) is the global average surface air temperature anomaly and its annual trend over time.For example,it is claimed that a +2C anomaly must not be exceeded without major climate consequences.Guardian poll reveals almost nine out of 10 climate experts do not believe current political efforts will keep warming below 2C.
Almost nine out of 10 climate scientists do not believe political efforts to restrict global warming to 2C will succeed,a Guardian poll reveals today.An average rise of 4-5C by the end of this century is more likely,they say,given soaring carbon emissions and political constraints.
Such a change would disrupt food and water supplies,exterminate thousands of species of plants and animals and trigger massive sea level rises that would swamp the homes of hundreds of millions of people.
The poll of those who follow global warming most closely exposes a widening gulf between political rhetoric and scientific opinions on climate change.While policymakers and campaigners focus on the 2C target,86% of the experts told the survey they did not think it would be achieved.A continued focus on an unrealistic 2C rise, which the EU defines as dangerous,could even undermine essential efforts to adapt to inevitable higher temperature rises in the coming decades,they warned.
The survey follows a scientific conference last month in Copenhagen,where a series of studies were presented that suggested global warming could strike harder and faster than realised.
The Guardian contacted all 1,756 people who registered to attend the conference and asked for their opinions on the likely course of global warming.Of 261 experts who responded, 200 were researchers in climate science and related fields.The rest were drawn from industry or worked in areas such as economics and social and political science.
The 261respondents represented 26 countries and included dozens of senior figures, including laboratory directors,heads of university departments and authors of the 2007 report from the Iintergovernmental Panel on Climate Change(IPCC).
The poll asked the experts whether the 2C target could still be achieved,and whether they thought that it would be met: 60% of respondents argued that,in theory,it was still technically and economically possible to meet the target, which represents an average global warming of 2C since the industrial revolution. The world has already warmed by about 0.8C
The poll comes as UN negotiations to agree a new global treaty to regulate carbon pollution gather pace in advance of a key meeting in Copenhagen in December.Officials will try to agree a successor to the Kyoto protocol, the first phase of which expires in 2012.The 2C target is unlikely to feature in a new treaty,but most of the carbon cuts proposed for rich countries are based on it. Bob Watson,chief scientist to Defra,told the Guardian last year that the world needed to focus on the 2C target,but should also prepare for a possible 4C rise.
Asked what temperature rise was most likely,84 of the182 specialists (46%) who answeredthe question saidit would reach 3-4C by the end of the century- 47 (26%) suggested a rise of 2-3C while a handful said 6C or more.While 24 experts predicted a catastrophic rise of 4-5C, just 18 thought it would stay at 2C or under.
Some of those surveyed who said the 2C target would be met confessed they did so more out of hope rather than belief."As a mother of young children I choose to believe this,and work hard toward it,"one said.
"This optimism is not primarily due to scientific facts, but to hope,"said another.Some said they thought bioengineering measures,such as seeding the ocean with iron to encourage plankton growth, would help meet the target.
Many of the experts stressed that an inability to hit the 2C target did not mean that efforts to tackle global warming should be abandoned, but that the emphasis is now on damage limitation.
Such a change would disrupt food and water supplies,exterminate thousands of species of plants and animals and trigger massive sea level rises that would swamp the homes of hundreds of millions of people.
The poll of those who follow global warming most closely exposes a widening gulf between political rhetoric and scientific opinions on climate change.While policymakers and campaigners focus on the 2C target,86% of the experts told the survey they did not think it would be achieved.A continued focus on an unrealistic 2C rise, which the EU defines as dangerous,could even undermine essential efforts to adapt to inevitable higher temperature rises in the coming decades,they warned.
The survey follows a scientific conference last month in Copenhagen,where a series of studies were presented that suggested global warming could strike harder and faster than realised.
The Guardian contacted all 1,756 people who registered to attend the conference and asked for their opinions on the likely course of global warming.Of 261 experts who responded, 200 were researchers in climate science and related fields.The rest were drawn from industry or worked in areas such as economics and social and political science.
The 261respondents represented 26 countries and included dozens of senior figures, including laboratory directors,heads of university departments and authors of the 2007 report from the Iintergovernmental Panel on Climate Change(IPCC).
The poll asked the experts whether the 2C target could still be achieved,and whether they thought that it would be met: 60% of respondents argued that,in theory,it was still technically and economically possible to meet the target, which represents an average global warming of 2C since the industrial revolution. The world has already warmed by about 0.8C
The poll comes as UN negotiations to agree a new global treaty to regulate carbon pollution gather pace in advance of a key meeting in Copenhagen in December.Officials will try to agree a successor to the Kyoto protocol, the first phase of which expires in 2012.The 2C target is unlikely to feature in a new treaty,but most of the carbon cuts proposed for rich countries are based on it. Bob Watson,chief scientist to Defra,told the Guardian last year that the world needed to focus on the 2C target,but should also prepare for a possible 4C rise.
Asked what temperature rise was most likely,84 of the182 specialists (46%) who answeredthe question saidit would reach 3-4C by the end of the century- 47 (26%) suggested a rise of 2-3C while a handful said 6C or more.While 24 experts predicted a catastrophic rise of 4-5C, just 18 thought it would stay at 2C or under.
Some of those surveyed who said the 2C target would be met confessed they did so more out of hope rather than belief."As a mother of young children I choose to believe this,and work hard toward it,"one said.
"This optimism is not primarily due to scientific facts, but to hope,"said another.Some said they thought bioengineering measures,such as seeding the ocean with iron to encourage plankton growth, would help meet the target.
Many of the experts stressed that an inability to hit the 2C target did not mean that efforts to tackle global warming should be abandoned, but that the emphasis is now on damage limitation.
We try our level best to dedicate "a pure and unpolluted earth" to our coming generation!
Suppose, I think it might be the assets,we are leaving behind us!!
Save Earth
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