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.
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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
Lightning's 'NOx-ious' Impact On Pollution, Climate
More than 1.2 billion lightning flashes occur around the world every year. Each of those billion lightning flashes produces a puff of nitrogen oxide gas (NOx) that reacts with sunlight and other gases in the atmosphere to produce ozone. Using data gleaned from aircraft observations and satellites, NASA scientists recently took steps toward a better global estimate of lightning-produced NOx and found that lightning may have a considerably stronger impact on the climate in the mid-latitudes and subtropics.
Seafloor Fossils Provide Clues On Climate Change
Deep under the sea, a fossil the size of a sand grain is nestled among a billion of its closest dead relatives. Known as foraminifera, these complex little shells of calcium carbonate can tell you the sea level, temperature, and ocean conditions of Earth millions of years ago. That is, if you know what to look for.
Changing Arctic Affecting Air, Ocean, And Everything In Between
Despite the fact that summer 2009 had more sea ice than in 2007 or 2008, scientists are seeing drastic changes in the region from just five years ago and at rates faster than anticipated.
Past Climate Of Northern Antarctic Peninsular Informs Global Warming Debate
The seriousness of current global warming is underlined by a reconstruction of climate at Maxwell Bay in the South Shetland Islands of the Antarctic Peninsula over approximately the last 14,000 years, which appears to show that the current warming and widespread loss of glacial ice are unprecedented.
Innovative Plan To Save Rainforest, Reduce Greenhouse Gas Emissions
An innovative proposal by the Ecuadorian government to protect an untouched, oil rich region of Amazon rainforest is a precedent-setting and potentially economically viable approach, says a team of environmental researchers.
Calm Before The Spawn: Climate Change And Coral Spawning
Biologists have explained why corals spawn for just a few nights in some places but elsewhere string out their love life over many months. A new study shows that corals spawn when regional wind fields are light. When it is calm, the eggs and sperm have the chance to unite before they are dispersed.
Green Is Cool, But US Land Changes Generally Are Not
Most land use changes occurring in the continental US result in raised regional surface temperatures, according to new research. The study found that almost any change that makes land cover less "green" contributes to warming. A perhaps less intuitive finding is that conversion of any land to agricultural use results in cooling, even land that was previously forested.
North Atlantic Fish Populations Shifting As Ocean Temperatures Warm
About half of 36 fish stocks in the Northwest Atlantic Ocean, many of them commercially valuable species, have been shifting northward over the last four decades, with some stocks nearly disappearing from US waters as they move farther offshore, according to a new study.
Newly Drilled Ice Cores May Be The Longest Taken From The Andes
Researchers spent two months this summer high in the Peruvian Andes and brought back two cores, the longest ever drilled from ice fields in the tropics. This latest expedition focused on a yet-to-be-named ice field 5,364 meters above sea level in the Cordillera Blanca mountain range.
Report On US-China Collaboration On Carbon Capture And Sequestration
Lawrence Livermore National Laboratory's Julio Friedmann, in collaboration with the Center for American Progress, the Asia Society Center and with partner Monitor Group, today released the report, "A Roadmap for US-China Collaboration on Carbon Capture and Sequestration."
Professor To Predict Weather On Mars
Is there such a thing as "weather" on Mars? There are some doubts, considering the planet's atmosphere is only 1 percent as dense as that of the Earth. Mars, however, definitely has clouds, drastically low temperatures and out-of-this-world dust storms. A professor of atmospheric sciences now hopes to analyze and forecast Martian weather.
Deep-sea Ecosystems Affected By Climate Change
Deep-sea ecosystems occupying 60 percent of the Earth's surface could be vulnerable to the effects of global warming, warn scientists.
Climate Change Could Create Agricultural Winners And Losers In East Africa, New Study Warns
As African leaders prepare to present an ambitious proposal to industrialized countries for coping with climate change in the part of the world that is most vulnerable to its impacts, a new study points to where and how some of this money should be spent. The study projects that climate change will have highly variable impacts on East Africa's vital maize and bean harvests over the next two to four decades.
Snows Of Kilimanjaro Shrinking Rapidly, And Likely To Be Lost
The remaining ice fields atop famed Mount Kilimanjaro in Tanzania could be gone within two decades and perhaps even sooner, based on the latest survey of the ice fields remaining on the mountain . The findings indicate a major cause of this ice loss is very likely to be the rise in global temperatures. Although changes in cloudiness and precipitation may also play a role, they appear less important, particularly in recent decades.
SMOS Satellite Successfully Launched: First-ever Satellite To Attempt To Measure Ocean Salinity From Space
A rocket carrying the European Space Agency's Soil Moisture and Ocean Salinity satellite blasted off successfully today. SMOS is the first-ever satellite to attempt to measure ocean salinity from space. It will provide global maps of soil moisture over land and surface salinity over the ocean.
Snail Fossils Suggest Semiarid Eastern Canary Islands Were Wetter 50,000 Years Ago
Isotopic measurements performed on fossil land snail shells found in ancient soils on the subtropical eastern Canary Islands resulted in oxygen isotope ratios that suggest the Spanish archipelago off the northwest coast of Africa has become progressively drier over the past 50,000 years, according to new research.
Iron Controls Patterns Of Nitrogen Fixation In The Atlantic
Scientists have discovered that interactions between iron supply, transported through the atmosphere from deserts, and large-scale oceanic circulation control the availability of a crucial nutrient, nitrogen, in the Atlantic. Their findings have potentially important implications for understanding global climate, both past and future.
Interactions With Aerosols Boost Warming Potential Of Some Gases
For decades, climate scientists have worked to identify and measure key substances -- notably greenhouse gases and aerosol particles -- that affect Earth's climate. And they've been aided by ever more sophisticated computer models that make estimating the relative impact of each type of pollutant more reliable. Yet the complexity of nature -- and the models used to quantify it -- continues to serve up surprises. The most recent? Certain gases that cause warming are so closely linked with the production of aerosols that the emissions of one type of pollutant can indirectly affect the quantity of the other. And for two key gases that cause warming, these so-called "gas-aerosol interactions" can amplify their impact.
Soil Moisture And Ocean Salinity Satellite Ready For Launch
A new European Earth observation satellite will be launched in the early hours of Monday November 2 from the Plesetsk Cosmodrome in northern Russia. The European Space Agency Soil Moisture and Ocean Salinity satellite will measure moisture levels in the Earth's soils and the saltiness of the world's oceans from space for the very first time.
Global Warming Cycles Threaten Endangered Primate Species
One of the first-ever analyses of the effects of global warming on endangered primates has examined how El Niņo warming has affected the abundance of four highly threatened New World monkeys. All four monkey species showed drops in abundance relating to large-scale climate fluctuations. The study suggests that the consequences of intensified climate fluctuations could be devastating for several primate species.