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Water risk as world warms. Dieter Telemans/Panos Water scarcity in parts of Africa could become worse, according to a complementary set of climate projections. When pondering the best way to study the impact of climate change, researcher Hans Joachim Schellnhuber liked to recall an old Hindu fable. Six men, all blind but thirsty for know­ledge, examine an elephant. One fumbles the pachyderm’s sturdy side, while others grasp at its tusk, trunk, knee, ear or tail. In the end, all are completely misled as to the nature of the beast. The analogy worked. The group warns that water is the biggest worry. “Water and all that relies on it, from food to sanitation and public health, is an emblematic aspect of climate change whose urgency people tend to instantly understand,” says Schellnhuber.

To assess what a warmer world might mean for the human race, 30 groups from 12 countries have run thousands of simulations, using a standardized set of scenarios for greenhouse-gas emissions. Global warming. Global mean land-ocean temperature change from 1880 to 2014, relative to the 1951–1980 mean. The black line is the annual mean and the red line is the 5-year running mean. The green bars show uncertainty estimates. Source: NASA GISS. The map shows the 10-year average (2000–2009) global mean temperature anomaly relative to the 1951–1980 mean. The largest temperature increases are in the Arctic and the Antarctic Peninsula. Source: NASA Earth Observatory[1] Fossil fuel related carbon dioxide (CO2) emissions compared to five of the IPCC's "SRES" emissions scenarios.

Global warming and climate change can both refer to the observed century-scale rise in the average temperature of the Earth's climate system and its related effects, although climate change can also refer to any historic change in climate. Scientific understanding of the cause of global warming has been increasing. Climate model projections were summarized in the 2013 Fifth Assessment Report (AR5) by the IPCC. Greenhouse gases. IPCC - Intergovernmental Panel on Climate Change.

Science: search results. Greenhouse Gases | Introduction. IntroductionWater VaporCO2CH4OzoneN2OCFCsCOAdditional Information Introduction What are greenhouse gases? Many chemical compounds present in Earth's atmosphere behave as 'greenhouse gases'. These are gases which allow direct sunlight (relative shortwave energy) to reach the Earth's surface unimpeded. As the shortwave energy (that in the visible and ultraviolet portion of the spectra) heats the surface, longer-wave (infrared) energy (heat) is reradiated to the atmosphere. Greenhouse gases absorb this energy, thereby allowing less heat to escape back to space, and 'trapping' it in the lower atmosphere. Water Vapor Water Vapor is the most abundant greenhouse gas in the atmosphere, which is why it is addressed here first.

As the temperature of the atmosphere rises, more water is evaporated from ground storage (rivers, oceans, reservoirs, soil). Carbon Dioxide The natural production and absorption of carbon dioxide (CO2) is achieved through the terrestrial biosphere and the ocean. Methane. Halocarbon. Ozone. Ozone /ˈoʊzoʊn/ (systematically named 1λ1,3λ1-trioxidane and μ-oxidodioxygen), or trioxygen, is an inorganic molecule with the chemical formula O 3(μ-O) (also written [O(μ-O)O] or O 3). It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope O 2, breaking down in the lower atmosphere to normal dioxygen. Ozone is formed from dioxygen by the action of ultraviolet light and also atmospheric electrical discharges, and is present in low concentrations throughout the Earth's atmosphere. In total, ozone makes up only 0.6 ppm of the atmosphere. Ozone's odor is sharp, reminiscent of chlorine, and detectable by many people at concentrations of as little as 10 ppb in air.

Ozone is a powerful oxidant (far more so than dioxygen) and has many industrial and consumer applications related to oxidation. Nomenclature[edit] The trivial name ozone is the most commonly used and preferred IUPAC name. History[edit] [edit] [edit] Ozone layer. The ozone layer refers to a region of Earth's stratosphere that absorbs most of the Sun's UV radiation. It contains high concentrations of ozone (O3) relative to other parts of the atmosphere, although it is still very small relative to other gases in the stratosphere. The ozone layer contains less than ten parts per million of ozone, while the average ozone concentration in Earth's atmosphere as a whole is only about 0.6 parts per million.

The ozone layer is mainly found in the lower portion of the stratosphere, from approximately 20 to 30 kilometres (12 to 19 mi) above Earth, though the thickness varies seasonally and geographically.[1] The ozone layer was discovered in 1913 by the French physicists Charles Fabry and Henri Buisson. The ozone layer absorbs 97–99% of the Sun's medium-frequency ultraviolet light (from about 200 nm to 315 nm wavelength), which otherwise would potentially damage exposed life forms near the surface.[2] Sources[edit] O2 + ℎνuv → 2O Ultraviolet light[edit] Policy. Nitrous oxide. Nitrous oxide, commonly known as laughing gas, nitrous, nitro, or NOS[1] is a chemical compound with the formula N 2O. It is an oxide of nitrogen. At room temperature, it is a colourless, non-flammable gas, with a slightly sweet odour and taste. It is used in surgery and dentistry for its anaesthetic and analgesic effects.

It is known as "laughing gas" due to the euphoric effects of inhaling it, a property that has led to its recreational use as a dissociative anaesthetic. It is also used as an oxidizer in rocketry and in motor racing to increase the power output of engines. At elevated temperatures, nitrous oxide is a powerful oxidizer similar to molecular oxygen.

Nitrous oxide gives rise to NO (nitric oxide) on reaction with oxygen atoms, and this NO in turn reacts with ozone. It is on the World Health Organization's List of Essential Medicines, a list of the most important medication needed in a health system.[3] Applications[edit] Rocket motors[edit] Internal combustion engine[edit] Methane. Arctic Methane Bubbles. Scientists are continually working to improve estimates of just how much methane, a potent greenhouse gas, is being emitted from the Arctic. A new study led by researcher Natalia Shakhova of the University of Alaska, Fairbanks, and the Russian Academy of Sciences' Far Eastern Branch reports that methane releases from one part of the Arctic Ocean are more than twice what scientists previously thought. Shakhova and her colleagues investigated releases of methane from permafrost underneath a shallow part of the Arctic Ocean called the East Siberian Arctic Shelf, which sits in the ocean north of Siberia and east of the Lena River Delta.

There, the underwater permafrost serves as a cap over methane in the seafloor. The permafrost is thawing, though and losing its ability to hold in the methane. "Thus, methane could release in large amounts," Shakhova said. Shakhova's research team used sonar to target bubbles of methane rising up from the seafloor. Threat of ‘Methane Time Bomb. 30 Oct 2008: Report by susan q. stranahan For the past 15 years, scientists from Russia and other nations have ventured into the ice-bound and little-studied Arctic Ocean above Siberia to monitor the temperature and chemistry of the sea, including levels of methane, a potent greenhouse gas. Their scientific cruises on the shallow continental shelf occurred as sea ice in the Arctic Ocean was rapidly melting and as northern Siberia was earning the distinction — along with the North American Arctic and the western Antarctic Peninsula —of warming faster than any place on Earth.

Until 2003, concentrations of methane had remained relatively stable in the Arctic Ocean and the atmosphere north of Siberia. But then they began to rise. Gustafsson said he makes no claims that the methane release “is necessarily driven by global warming.” Enlarge Image International Siberian Shelf Study Map: Siberian expedition route France, Germany, and Spain combined. Methane Emissions. Methane (CH4) is the second most prevalent greenhouse gas emitted in the United States from human activities. In 2013, CH4 accounted for about 10% of all U.S. greenhouse gas emissions from human activities.

Methane is emitted by natural sources such as wetlands, as well as human activities such as leakage from natural gas systems and the raising of livestock. Natural processes in soil and chemical reactions in the atmosphere help remove CH4 from the atmosphere. Methane's lifetime in the atmosphere is much shorter than carbon dioxide (CO2), but CH4 is more efficient at trapping radiation than CO2. Pound for pound, the comparative impact of CH4 on climate change is 25 times greater than CO2 over a 100-year period. Globally, over 60% of total CH4 emissions come from human activities. [1] Methane is emitted from industry, agriculture, and waste management activities, described below.

Industry. Methane is also emitted from a number of natural sources. Top of page Emissions and Trends References. Carbon dioxide. Carbon dioxide (chemical formula CO2) is a naturally occurring chemical compound composed of 2 oxygen atoms each covalently double bonded to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state, as a trace gas at a concentration of 0.039 per cent by volume.[1] The environmental effects of carbon dioxide are of significant interest. Atmospheric carbon dioxide is the primary source of carbon in life on Earth and its concentration in Earth's pre-industrial atmosphere since late in the Precambrian eon was regulated by photosynthetic organisms.

Carbon dioxide is an important greenhouse gas; burning of carbon-based fuels since the industrial revolution has rapidly increased the concentration, leading to global warming. History Chemical and physical properties Structure and bonding The carbon dioxide molecule is linear and centrosymmetric. In aqueous solution The hydration equilibrium constant of carbonic acid is (at 25 °C). .

Uses. GreenHouse Gas Online. Most potent greenhouse gas detected. A long-lived greenhouse gas more potent than any other — at least by one measure — has been detected in the atmosphere by Canadian researchers. Perfluorotributylamine (PFTBA) has a radiative efficiency of 0.86 — the highest of any chemical found to date, reported chemists from the University of Toronto in a recent issue of Geophysical Research Letters.

Radiative efficiency is one measure of a chemical's effectiveness at warming the climate, per part per billion of volume. Greenhouse gases make the Earth warmer by absorbing and trapping heat that would otherwise escape from the atmosphere. The biggest contributor to climate change is carbon dioxide because its concentrations are so high — 393.1 parts per million in 2012 — and growing, thanks to human activity such as the burning of fossil fuels. However, many other gases with smaller concentrations also contribute.

Greenhouse gas levels hit new record high Chemical sold for 30 years Detected at 3 sites in Toronto. Ted talks about global issues. Climate Reality. The Great Global Warming Swindle -- A Summary. [First published on Google Knol on September 20th, 2008] Summary There are scientists who dispute the popular belief about the cause of global warming, also known as climate change. They have identified five reasons why man-made production of carbon dioxide cannot cause global warming. They believe that climate change is an entirely natural process. Introduction This article is a summary of the documentary called The Great Global Warming Swindle (2007). Origin of the man-made climate change hypothesis The man-made climate change hypothesis originated at a time when the global temperature was falling.

Two things happened to change the main-stream view about climate change. Why the man-made climate change hypothesis is wrong There are five key reasons why the man-made climate change hypothesis is wrong. Climate change is a natural occurrence The earth's climate has always changed. Global temperature fell during the period of greatest man-made carbon dioxide production Rising global temperature. Climate Change.