Global Warming

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What is Global Warming aka Climate Change?
Global warming is the increase of the average temperature in the atmosphere and oceans over time due primarily to human influences. Since the late 19th century, scientists have monitored the fluctuations in temperature and studied global warming theories and trends to determine the causes and to assess the extent to which they are due to human activity. The greenhouse effect is largely caused by human-generated carbon dioxide (CO₂) and, to some extent, by increases in solar activity. The term "global warming" is used to imply a human influence while "climate change" is most often used in association with changes in climate with no easily identifiable cause, such as the processes that produced the Ice Ages.

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Current climate models (simulations) based on estimates of increasing CO₂ and, to a lesser extent, by decreasing sulfate aerosols, predict that temperatures will increase by 1.4-5.8°C (2.5-10.4°F) between 1990-2100. This is a somewhat wide range; however, it is difficult to predict CO₂ emissions because of the number of variables involved. Some climate studies have shown that, even in the absence of the CO₂ emission variable, global climate will increase by 0.5°C (0.9°F) over the next one hundred years due to warming caused just by the ocean. In addition, models predict that sea levels will rise by about 10 cm over the next century.

Evidence of global warming includes decreased snowfall, rising sea levels and changes to weather trends. Precipitation levels, precipitation patterns, cloud cover, severe weather, and other elements will be impacted by the increase in greenhouse gas concentrations in the atmosphere. "Greenhouse gases" are so named because they trap radiant energy from the sun that would otherwise be radiated back into space.

Climate Change FAQ from the Scripps Institution of Oceanography, UC San Diego »

The Kyoto Protocol was developed by the United Nations Framework Convention on Climate Change (UNFCCC) as an international agreement to reduce greenhouse gas emissions worldwide. The Protocol was entered into force in February 2005, and signed by countries committed to reducing CO₂ emissions and 5 other greenhouse gases. They may also engage in emissions trading, or the purchase of credits from other countries that remain under the limits of greenhouse gas emissions. In this way, countries that may exceed the limits can still comply with the protocol. To date, 141 countries have ratified the agreement. Unfortunately, neither the United States nor Australia have been participating, which has generated speculation as to whether the Kyoto Protocol will successfully reduce greenhouse gases, even if completely implemented by all signed countries.

Global climate change has been studied on a large scale based on analyses of global temperature fluctuations over thousands of years; for example, since the last Ice Age, which occurred approximately 12,000 years ago, global temperatures have been relatively stable. Studies on a smaller scale, however, show that temperatures in the lower troposphere have increased between 0.08 and 0.22°C per decade since 1979. Still, these modern day changes are not always linear, which has created a source of debate within the scientific community and the news media.

Al Gore's presentation New thinking on the climate crisis (March, 2008) on TED (technology, entertainment, design). If you haven't visited TED, which features talks from many of the world's greatest minds - we highly recommend it.

The study of paleoclimatology (ancient climates) is increasingly linked to modern day climate study. For example, the Earth was in an ice age for the last 160,000 years prior to the end of the last Ice Age. Earlier studies of this time period showed little variability in temperatures; however, more recent studies showed the variability to be about twice as great as previously published, indicating that temperature fluctuations are more frequent throughout time than first thought. However, this does not negate the impact of human activity on the current rate of global warming.

Climate change is caused by both natural and external forces, the latter including both human—greenhouse gases—and non-human causes such as changes in the Earth's orbit around the Sun, solar activity, and volcanic emissions. Science is increasingly pointing to human activities as the reason that global warming is accelerating.

The greenhouse gas theory started in the 19th century when the Swedish chemist and 1903 Nobel Laureate, Svante Arrhenius, determined that increases in greenhouse gas concentration would lead to higher global mean temperatures, while decreases would lead to colder global mean temperatures. His finding was a result of his research on ice ages, and was largely rejected by his peers at the time. A colleague of Arrhenius, Arvid Högbom, was one of the first scientists to study the carbon cycle. Arrhenius used his data to base his assessment that in 1890, emission and absorption of CO₂ in the atmosphere were roughly in balance, and that burning fossil fuels would not cause problems. However, this was based solely on the use of coal, not on the use of fossil fuels in the automobile and other industries.

The acceptance that human greenhouse gas emissions are contributing to the warming of the Earth's atmosphere is increasing; however, opponents to this theory remain, largely due to several confounding factors to the theory. For example, water vapor, naturally present in the Earth's atmosphere in the form of humidity and clouds, is also a strong greenhouse gas. The vapor affects the climate by cooling the Earth's surface by reflecting sunlight and blocking radiation of heat away from the surface. The presence of CO₂ may alter the distribution of clouds, in which case the climate could be further affected by human generated greenhouse gases. However the extent to which CO₂ emissions alter cloud cover is not well known. In the 2001 Intergovernmental Panel on Climate Change (IPCC) report on climate change, changes in cloud cover were mentioned as an important factor in predicting future climate change.

Save Our Planet - The Latest News on Climate Change

Opponents to the global warming theory postulate that water vapor and clouds will cancel out warming effect of CO₂ emissions. However, the warming trends over the past few decades are increasingly negating the cancellation hypothesis. Furthermore, sophisticated computer models of the climate, validated by the scientific community in demonstrating accurate simulations of known climate variations such as El Niño events, have predicted that adding CO₂ to the atmosphere will create a warmer climate in the future. The degree to which this warming will occur varies by model, however, and opponents of the global warming theory point out variables that models are not equipped to factor, such as changes in vegetation and cloud cover.

In spite of the dying debate, it is known that coal-burning power plants, automobile exhausts, factory smokestacks, and other waste vents contribute about 22 billion tons of CO₂ (6 billion tons of pure carbon) and other greenhouse gases into the earth's atmosphere each year. CO₂ levels have increased by about 31% since 1750, about 75% of which can be attributed to fossil fuel burning. The remaining 25% is largely due to land-use change, particularly deforestation.

In their 2006 report, the IPCC stated that the atmospheric concentration of CO₂ has exceeded levels over the natural range for the last 650,000 years. The consensus is that human activity is, in almost all aspects of global warming, the most likely cause. This is a change from the previous report that stated human activity was merely a likely cause.

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Global Warming News [ScienceDaily]

After mastodons and mammoths, a transformed landscape
Roughly 15,000 years ago, at the end of the last ice age, North America's vast assemblage of large animals -- including such iconic creatures as mammoths, mastodons, camels, horses, ground sloths and giant beavers -- began their precipitous slide to extinction.

Sustainable farming may help maintain healthy climate
Sustainable farming, initially adopted to preserve soil quality for future generations, may also play a role in maintaining a healthy climate, according to researchers.

Paleontologists find extinction rates higher in open-ocean settings during mass extinctions
Researchers have uncovered a strikingly pattern for ancient mass extinctions: extinctions rates during mass extinctions were significantly higher in open-ocean-facing settings than in epicontinental seas, indicating that open-ocean settings were more susceptible to the mass-extinction-causing agents.

Oceans' uptake of human-made carbon may be slowing
The oceans play a key role in regulating climate, absorbing more than a quarter of the carbon dioxide that humans put into the air. Now, the first year-by-year accounting of this mechanism during the industrial era suggests the oceans are struggling to keep up with rising emissions -- a finding with potentially wide implications for future climate.

Mysteriously warm times in Antarctica
A new study of Antarctica's past climate reveals that temperatures during the warm periods between ice ages (interglacials) may have been higher than previously thought. The latest analysis of ice core records suggests that Antarctic temperatures may have been up to 6°C warmer than the present day.

Diatoms reveal climate changes
Some 500 years ago there was a change in the circulation in the atmosphere over Scandinavia. This probably led to increased amounts of winter precipitation in northern Sweden for a period.

Dozen lesser-known chemicals have strong impact on climate change
A new study indicates that major chemicals most often cited as leading causes of climate change, such as carbon dioxide and methane, are outclassed in their warming potential by compounds receiving less attention.

Monsoon model indicates potential for abrupt transitions
A self-amplifying effect presently sustains monsoon winds, but it could also disrupt the circulation over land and sea. The periodical rainfall could stop from one season to another or for months within seasons. High air pollution could lead to the disruption. Global warming increases the risk of abrupt monsoon transitions from high-precipitation to dry periods.

Research challenges for understanding landscape changes identified
Nine research challenges and four research initiatives that are poised to advance the study of how Earth's landscapes change were unveiled by the National Research Council.

Fossil fuel carbon dioxide emissions up by 29 percent since 2000
The strongest evidence yet that the rise in atmospheric carbon dioxide emissions continues to outstrip the ability of the world's natural "sinks" to absorb carbon has just been published.

New water management tool may help ease effects of drought
Continued improvement of climate forecasts is resulting in better information about what rainfall may look like months in advance. A researcher has now developed an innovative water management framework that would take advantage of these forecasts to plan for droughts or excess rain in order to make the most efficient use of an area's water resources.

How much water does the ocean have?
The calculation of variations in the sea level is relatively simple. It is by far more complicated to then determine the change in the water mass. A team of geodesists and oceanographers have now, for the first time succeeded in doing this. The researchers were able to observe short-term fluctuations in the spatial distribution of the ocean water masses. Their results are, amongst others, important for improved climate models.

Ancient high-altitude trees grow faster as temperatures rise
Increasing temperatures at high altitudes are fueling the post-1950 growth spurt seen in bristlecone pines, the world's oldest trees, according to new research. The pines near treeline have wider annual growth rings for the period from 1951 to 2000 than for the previous 3,700 years. Regional temperatures, particularly at high elevations, have increased during the same 50-year time period. The finding is another example of changes in high-elevation ecosystems that are linked to warming temperatures.

Sea stars bulk up to beat the heat
A new study finds that a species of sea star stays cool using a strategy never before seen in the animal kingdom. The sea stars soak up cold sea water into their bodies during high tide as buffer against potentially damaging temperatures brought about by direct sunlight at low tide.

Alternative animal feed part of global fisheries crisis fix
Finding alternative feed sources for chickens, pigs and other farm animals will significantly reduce pressure on the world's dwindling fisheries while contributing positively to climate change, according to researchers.

Link between climate change and cattle nutritional stress examined
A group of researchers has found that any future increases in precipitation would be unlikely to compensate for the declines in forage quality that accompany projected temperature increases.

New climate treaty could put species at risk, scientists argue
Plans to be discussed at the forthcoming UN climate conference in Copenhagen to cut deforestation in developing countries could save some species from extinction but inadvertently increase the risk to others, scientists believe.

Penguins and sea lions help produce new atlas
Recording hundreds of thousands of individual uplinks from satellite transmitters fitted on penguins, albatrosses, sea lions, and other marine animals, the Wildlife Conservation Society and BirdLife International have released the first-ever atlas of the Patagonian Sea -- a globally important but poorly understood South American marine ecosystem.

Optical properties of the Antarctic system and new radiation information
The Antarctic system comprises of the continent itself, Antarctica, and the ocean surrounding it, the Southern Ocean. In a new study, measurements were made during three Austral summers to study the optical properties of the Antarctic system and to produce radiation information for additional modeling studies.

Lab machine to study glacial sliding related to rising sea levels created
Researchers have created a glacier in a freezer that could help scientists understand how glaciers slide across their beds. That could help researchers predict how climate change accelerates glacier sliding and contributes to rising sea levels.

[ScienceDaily Global Warming News...]

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