The dictionary defines the word environment as surroundings all conditions, circumstances, and influences surrounding, and affecting the development of, an organism or a group of organisms.

It is the complex of physical, chemical, and biotic factors that act upon an organism or an ecological community and ultimately determine its form and survival.

The Earth's environment is treated in a number of articles.

The major components of the physical environment are discussed in the articles Atmosphere, Climate and Weather, Continental Landforms, Hydrosphere, and Oceans.

The relationship between the principal systems and components of the environment, and the major ecosystems of the Earth are treated in the article Biosphere.

The significant environmental changes that have occurred during Earth's history are surveyed in the article Geochronology.

The pollution of the environment and the conservation of its natural resources are treated in the article Conservation of Natural Resources.

Hazards to life in the biosphere are discussed in the articles Death, Disease, and Immunity.


Antarctic ozone hole splits in two October 2002 - CNN

Like a giant amoeba in the sky, the ozone hole above Antarctica has divided into two parts, which have spread away from the southernmost continent.

Ozone hole 'heading for Europe' BBC - November 2001
A small "hole" in the ozone layer is opening up over the North Atlantic and heading for Europe

Ozone hole larger than ever, scientists say

September 8, 2000 - AP

The hole in the ozone layer is now three times larger than the United States -- the largest its ever been, scientists at NASA said Friday. U.N. weather experts said the hole over the Antarctic is growing earlier in the year than usual.

Measurements of ozone depletion vary from year to year, making it difficult for scientists to determine the long-term environmental impact of changes in the ozone layer. Still, this year's hole caught atmospheric experts off-guard.

"The fact that it's real big right now is kind of a surprise," said Dr. Paul A. Newman of NASA's Goddard Space Flight Center in Greenbelt, Md.

The center detected an ozone hole of about 11 million square miles on Sept. 3. That was the biggest ever, beating the previous record of 10.5 million square miles on Sept. 19, 1998, it said.

In Geneva, the U.N. World Meteorological Observation said stations in the Antarctic reported decreases in ozone of between 10 percent and 50 percent compared with the period between 1964 and 1976, before the ozone hole was observed. Though ozone levels decrease each year starting in July, such a large drop was "unprecedented" this early in the season, the WMO said Friday.

"It is remarkable to find these low values so early in September, perhaps one or two weeks earlier than in any previous year," the agency said.

Experts stressed that atmospheric variations from year to year combine with manmade gases to determine the hole's size. They said they can't be certain what the measurements mean for the rest of this year and beyond.

Depletion of the ozone layer over Antarctica and the Arctic is being monitored because ozone protects Earth from harmful ultraviolet radiation. Too much UV radiation can cause skin cancer and destroy tiny plants at the beginning of the food chain.

Antarctic ozone depletion starts in July, when sunlight triggers chemical reactions in cold air trapped over the South Pole during the Antarctic winter. It intensifies during August and September before slackening in October as temperatures rise.

Circular winds, known as a vortexes, trap air, giving chemicals the chance to react with the ozone.

"The polar vortex is bigger this year -- bigger than 1998," Newman said. "The containment vessel is larger and so the size is larger."

Its size raises concerns that "we're perhaps beginning to see some evidence of climate change in the stratosphere," although no firm evidence is available, he said.

"Maybe we have to be a little more serious about looking at this problem of the interaction of global warming and stratosphere cooling and ozone loss," he added.

The strength of the vortex means the ozone hole may persist a few days longer than usual, breaking up in December, Newman said.

Chlorine compounds used in refrigerants, aerosol sprays, solvents, foam-blowing agents and bromine compounds used in firefighting halogens cause most ozone depletion.

The temperature over Antarctica also contributes significantly to the size of each year's hole. Starting in October, warmer temperatures reduce the ability of chlorine and other gases to destroy ozone.

"It's driven just about as much now by the temperature of the air as by the amount of fluorocarbons in there," said Russ Schnell, deputy director of the National Oceanic and Atmospheric Administration's climate change laboratory in Boulder, Colo.

Newman said he expects that ozone levels inside the Antarctic area covered by the hole will continue to drop over the coming week, but he said the area of the hole has stabilized over the past week and is unlikely to grow significantly.

"The true story won't come out for another three or four weeks," Schnell said.

Experts agree that the manmade chemicals are leveling off thanks to the Montreal Protocol, which commits countries to eliminating production and use of ozone-depleting substances. But it could be 20 years before ozone levels recover noticeably.

Joe Farman, a consultant at the European Ozone Research Coordination Unit in Cambridge, England, said this year's hole is the biggest for this time of year, though it is not that much larger than 1996 or 1998.

But "one thing's quite clear -- there's no sign of recovery yet," he said.

Magazine: Mediterranean Shrinks While Oceans Rise

June 15, 2000 - Reuters - London

Sea levels have been rising around the globe for the past 40 years but the Mediterranean is shrinking, New Scientist magazine said Wednesday.

Global warming has increased ocean levels by more than one millimeter (0.04 inch) a year for the past century but since 1960 the Mediterranean has lost as much as 1.3 millimeters (0.05 inch) annually.

``The change is dramatic,'' said Michael Tsimplis, of the Southampton Oceanography Center in southern England.

He discovered the discrepancy by analyzing long-term tidal gauges on the sea. Tsimplis attributes much of the problem to increased salinity and density as well as dam building.

``Since 1960, rising air pressure over the sea has reduced rainfall, bumping up salinity. Rivers that bring fresh water into the sea have also been dammed,'' according to the weekly science journal.

He claimed the water becomes more dense as the salinity increases and it takes up less space.

Putting a price on clean air

Countries are under pressure to cut carbon emissions

June 16, 2000 - BBC

On a hillside created by decades of rubbish from the citizens of Hamburg, a giant wind turbine helps supply the energy needs of Germany's second city.

The local electricity company which built it now has to produce slightly less power from its coal-fired station across the River Elbe.

By making that change, the company has earned what are known as emission reduction credits.

These could be used towards Germany's targets to cut the greenhouse gases like carbon dioxide which many scientists now believe are heating up the Earth's atmosphere.

But Hamburg Electricity has decided instead to become the first European company to put those credits on the international market.

It is selling them to Canada's second largest polluter, the TransAlta Corporation of Calgary, the BBC has learned.

Market and loopholes

TransAlta generates electricity from coal, and hopes to be able to use those credits towards meeting its own obligations to cut pollution under the Kyoto treaty agreed two and a half years ago, though still not in force.

The deal has been set up by the New York brokers Natsource, one of a number of international financial traders specialising in this embryonic market.

It was created by the prospect of legally-binding cuts in greenhouse gas emissions.

Garth Edwards of Natsource says the Canadian company would find it extremely expensive to make all the required cuts in its own operations, and is choosing instead to buy some of the reductions made in Germany.

Some environmental groups fear this market-based system could provide loopholes for major polluters wanting to escape the changes necessary to slow down global warming.

But supporters of the scheme claim it should help turn the aims of Kyoto into reality.

Treaty doubts

UK firms like Zetec Power, which is developing emission-free vehicle engines powered by hydrogen fuel cells, believe the growing demand for these credits will help pump cash into cleaner technology.

Zetec's Gerard Sauer says the finance available from this market, estimated at �900m a year in Britain alone, should make it easier for the company's products to become economically competitive.

There are still strong doubts about whether the United States, the world's biggest polluter, will ratify the Kyoto treaty, and even if it does come into force the rules governing these trades are far from clear.

A UN conference at the Hague in November is due to settle the remaining arguments about the working of the agreements.

But while the world's politicians continue to bicker, a growing number of companies are deciding they cannot afford to wait to see how the debate turns out.

The market in cleaner air is joining oil futures and pork bellies as a scarce commodity ripe for speculation.

Hamburg has invested in wind power