Global Warming
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.
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.
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
Prehistoric response to global warming informs human planning today
Since 2004, University at Buffalo anthropologist Ezra Zubrow has worked intensively with teams of scientists in the Arctic regions of St. James Bay, Quebec, northern Finland and Kamchatka to understand how humans living 4,000 to 6,000 years ago reacted to climate changes.
More maize ethanol may boost greenhouse gas emissions
Mandated increases in the production of maize-derived ethanol will lead to land-use changes that boost carbon dioxide emissions enough to make the fuel a worse environmental option than burning gasoline, according to a new analysis.
Aquatic 'dead zones' contributing to climate change
The increased frequency and intensity of oxygen-deprived "dead zones" along the world's coasts can negatively impact environmental conditions in far more than local waters. Scientists explain that the increased amount of nitrous oxide produced in hypoxic waters can elevate concentrations in the atmosphere, further exacerbating the impacts of global warming and contributing to ozone "holes" that increase our exposure to harmful UV radiation.
Impacts of changing climate on ocean biology
A three-year field program now underway is measuring carbon distributions and primary productivity in the Northwest Atlantic Ocean to help scientists worldwide determine the impacts of a changing climate on ocean biology and biogeochemistry.
Predicting future climate: Networking initiative to support interdisciplinary research
Specialists from various Earth system science disciplines recently gathered to address a major question: what will our environment look like in the future? Of course, possible answers to this question raise even more questions. For instance, if changing climatic conditions were to alter local vegetation, how would this new landscape react to future climatic trends? Answering these questions with certainty would allow us to manage better our natural resources by defining appropriate planning and mitigation actions.
Ever-changing Earth: How the atmosphere can affect planet's shape, rotation, gravitational field
Researchers in Austria are investigating the effects of the Earth's atmosphere on our planet's shape, its rotation and its gravitational field. The researchers' aim is to develop a better understanding of the Earth's system and to support the development of the Global Geodetic Observing System (GGOS).
Learning from nature: Scientists break down carbon dioxide into carbon monoxide using visible light
A recent discovery in understanding how to chemically break down the greenhouse gas carbon dioxide into a useful form opens the doors for scientists to wonder what organism is out there -- or could be created -- to accomplish the task. Scientists have figured out a way to efficiently turn carbon dioxide into carbon monoxide using visible light, like sunlight.
Increased solar radiation requires additional CO2 reduction of 50 million tonnes, analysis finds
The recently observed reduction in air pollution implies that more solar radiation reaches Earth’s surface. This could lead to a far more rapid increase in Earth’s temperature in the coming decades than has previously been expected. In order to successfully combat global warming, it is crucial that scientists incorporate increases in CO2 emissions reductions as well as reductions in air pollution in the calculations, according to a new analysis based on unique solar radiation data collected from weather stations between 1959 and 2002.
Carbon emissions 'outsourced' to developing countries
Scientists report that over a third of carbon dioxide emissions associated with consumption of goods and services in many developed countries are actually emitted outside their borders. The study finds that, per person, about 2.5 tons of carbon dioxide are consumed in the US but produced somewhere else. For Europeans, the figure can exceed four tons per person. Most of these emissions are outsourced to developing countries, especially China.
Climate fluctuations 115,000 years ago: Were short warm periods typical for transitions to glacial epochs?
At the end of the last interglacial epoch, around 115,000 years ago, there were significant climate fluctuations. In Central and Eastern Europe, the slow transition from the Eemian Interglacial to the Weichselian Glacial was marked by a growing instability in vegetation trends with possibly at least two warming events. This is the finding of German and Russian climate researchers who have evaluated geochemical and pollen analyses of lake sediments in Saxony-Anhalt, Brandenburg and Russia.
Snowball Earth: New evidence hints at global glaciation 716.5 million years ago
Geologists have found evidence that sea ice extended to the equator 716.5 million years ago, bringing new precision to a "snowball Earth" event long suspected to have taken place around that time. The new findings -- based on an analysis of ancient tropical rocks that are now found in remote northwestern Canada -- bolster the theory that our planet has, at times in the past, been ice-covered at all latitudes.
Methane releases from Arctic shelf may be much larger and faster than anticipated
A section of the Arctic Ocean seafloor that holds vast stores of frozen methane is showing signs of instability and widespread venting of the powerful greenhouse gas, according to new research.
Warming coastal water, thinning marine populations: Tracking of 2010 El Niño reveals marine life reductions
The ongoing El Niño of 2010 is affecting north Pacific Ocean ecosystems in ways that could affect the West Coast fishing industry, according to scientists. Researchers report a stronger than normal northward movement of warm water up the Southern California coast, a high sea-level event in January and low abundances of plankton and pelagic fish -- all conditions consistent with El Niño.
Mass loss from Alaskan glaciers overestimated? Previous melt contributed a third less to sea-level rise than estimated
The melting of glaciers is well documented, but when looking at the rate at which they have been retreating, a team of international researchers steps back and says not so fast. Previous studies have largely overestimated mass loss from Alaskan glaciers over the past 40-plus years, according to a new study that recalculates glacier melt in Alaska.
Chemicals that eased one environmental problem may worsen another
Chemicals that helped solve a global environmental crisis in the 1990s -- the hole in Earth's protective ozone layer -- may be making another problem -- acid rain -- worse, scientists are reporting. A new study analyzes the effect of chemicals that replaced the ozone-destroying chlorofluorocarbons once used in aerosol spray cans, air conditioners, refrigerators, and other products.
El Niño and a pathogen, not global warming, killed Costa Rican toad
Scientists broadly agree that global warming may threaten the survival of many plant and animal species; but global warming did not kill the Monteverde golden toad, an often cited example of climate-triggered extinction, says a new study.
Antifreeze proteins can stop ice melt, new study finds
The same antifreeze proteins that keep organisms from freezing in cold environments also can prevent ice from melting at warmer temperatures, according to a new study.
Ancient corals hold new hope for reefs
Fossil corals, up to half a million years old, are providing fresh hope that coral reefs may be able to withstand the huge stresses imposed on them by today's human activity. Reef ecosystems were able to persist through massive environmental changes imposed by sharply falling sea levels during previous ice ages, an international scientific team has found. This provides new hope for their capacity to endure the increasing human impacts forecast for the 21st century.
Understanding global climate change through new breakthroughs in polar research
Scientists have investigated the distribution and abundance of Antarctica's vast marine biodiversity with the Census of Antarctic Marine Life.
Ancient DNA from rare fossil reveals that polar bears evolved recently and adapted quickly
DNA from a rare, ancient polar bear fossil is yielding information about the response of the species to the devastation wrought by past climate changes. Analyses of the fossil's DNA reveals key pieces of the evolutionary history of both polar bears and brown bears. The fossil's DNA is, by far, the oldest mammal mitochondrial genome to be sequenced -- about twice the age of the oldest genome sequence from a woolly mammoth.
