The two most serious threats facing the world are global warming and the '6th extinction'. Both are man-made threats. The world is warming up due to the accumulation of carbon dioxide and other greenhouse gases spewed out by mainly by motor vehicles and factories.

Global warming will change the climate all over the world with unknown consequences. But, given that plants and animals, including humans definitely, have adapted to a particular climate-influenced environment, we can expect major upheavals when the climate patterns shift.

By 2080 it is believed that the summer ice cover of the Arctic will be completely gone. Since ice reflects away sunlight thus cooling the planet, without it, the earth will warm up further. Also the melting of the ice will add a lot of fresh water into the northern oceans.

This could stop the flow of the Gulf Stream bringing warmth from the tropics to Europe and North America. These areas could then experience massive cooling that could make them unlivable. The paleo-record suggests that when the outflow of water from the Arctic Basin hits a critical level of freshness, the global ocean circulation changes dramatically, as reported by the Scientific American magazine.

The process is on its way. Over the past 60 years, the discharge from Russian rivers into the Arctic has increased by 7 percent, and it is compounded by a record amount of melting from the Greenland Ice Sheet and Alaskan glaciers.

Also, a warmer climate means that the atmospheric as well as the oceanic systems would have more energy and therefore rains and storms could be heavier and more violent. This would be true in some places, for example, Europe, but in other places, such as Saharan Africa, it could be drier. The trend of heavier rains in Europe and a drier Saharan Africa is already taking place.

The melting of ice from the polar regions as well as the expansion of sea water due to the warming will increase the sea level, drowning many low lying areas. This could include many islands in the south Pacific and even cities such as London and New York, as warned by David King, the chief scientific advisor to the British government. Georgetown in Penang could be submerged, too.

Window of opportunity

The difference in sea levels between the earth's warm phase and cold phase can be drastic. 12,000 years ago, during the last ice age, the sea level was some 350 feet below present level, a warm phase.

Such was the situation that Sumatra, Java, Peninsula Malaysia and Borneo were one massive land mass joined to the Asian mainland, and New Guinea was joined with Australia. Thus, it would not at all be inconceivable that the release of the permanently frozen ices of the polar regions could drown a lot of land.

Warming of the oceans would mean more carbon dioxide be released into the atmosphere thus worsening the warming. Note that 50 percent of all carbon dioxide emitted since the industrial revolution is trapped in the oceans. With this release, beyond a certain point, there would be a runaway warming and thus climate change too. At this point it would be too late to do anything to control it. The window of opportunity would be closed.

With these changes to the environment, the eco-system and its inhabitants would be hard-pressed to adapt. It is believed that the change in climate would be far too rapid for a smooth adaptation by its inhabitants. The heat wave of 2003 in Europe, a sign of global warming, caused some 30,000 deaths.

The concentration of carbon dioxide in the atmosphere, 379 parts per million (ppm), is the highest for 420 thousand years according to King. The level is higher by 50 percent than the highest level within this time frame. And it is increasing at the rate of two parts per million every year.

If nothing is done to combat emissions, if it is business as usual, the earth will reach 1,000 ppm by 2100, which was the level 60 million years ago. Then, there was no ice at all on earth. If we reached that level, King says, the only place habitable for us would be Antarctica. The rest of the world would not sustain life.

Do not expect too much from the much touted hydrogen fuel cells to solve the carbon emissions. Scientific American reports that the energy conversion efficiency to transform one form of energy (for example oil) into hydrogen is too low even though the fuel cell itself is efficient

Given the climate change grave threat, are we doing anything to combat it? Not really. First, some scientists quibble whether human activity is indeed the cause for the increase in carbon concentration. (I suspect these are industry-backed scientists or those who still want to enjoy their Range Rovers without a bad conscience.)

Now, even the United Nations Intergovernmental Panel on Climate Change, after much horse-trading, finally acknowledges that humans are indeed responsible for the increase.

But still, the US - the most polluting country, accounting for some 25 percent of the carbon emissions - goes on quibbling about the cause.

The current administration will not sign the Kyoto Protocol to reduce carbon levels. Of course it is not strange that President George W Bush is not signing given that his funding comes from the powerful business lobby, especially the oil industry. Interestingly, the Pentagon recently says that climate change is the biggest enemy facing the US, not terrorism.

Extinction expected

Scientists are beginning to talk of the other grave threat, the so-called '6th extinction'. It is 6th because in the history of the earth there has been five major mass extinctions of species, where between 65-95 percent of the world's species died out. The last was when the dinosaurs perished, some 65 million years ago.

All five were natural disasters that caused the climate to change but the 6th will be man-made. This is due to, among others, habitat destruction (through the cutting down of forests, clearing wetlands, mangroves and other eco-systems, as well as polluting the air, land, rivers and oceans), and over-exploitation by humans and through global warming, again.

Depending on the best to the worse case scenarios of climate change, the extinction of land animals and plants could be between a third to a half of the present total species by 2050 as reported by the New Scientist magazine.

Coral reefs, the ocean equivalent of tropical rainforests, apart from being poison by our effluents, are also affected by global warming. It prevents the formation of new corals as well as their 'bleaching', thus killing them. If warming is high enough, the corals of the Great Barrier Reef could be decimated by 2050.

Comes a point (in 50, 100 years?) after more destruction of the eco-system, it will collapse beyond repair. The eco-system will start winding down and with it its inhabitants. Most likely, this time around, homo sapiens - no less than 'the thinking men' - will go down with it.

If the dinosaurs survived for some 150 million years, humans would just be a blip at some 150 thousand years. Some species might survive. And undoubtedly the world will survive given enough time, as it has in the previous extinctions.

Just don't count us in to rebuild the next world. The earth will get by without us.

ROSLI OMAR is an academic interested in the impact of science and technology on society and environment - being bred on the white-heat of technology creed himself.