There is a posting on this blog titled "The Other Side Of Global Warming". The posting discussed a side of global warming that does not get anywhere near as much attention as the increasing amount of carbon in the air. The removal of hundreds of millions of trees to make way for development has reduced the carbon sink that trees provide. Not only are we putting more carbon in the air, we are removing the trees that would have absorbed carbon from the air during their growth.
One of the perils of even a slight overall warming of the earth is extremely powerful and destructive hurricanes, and other wild weather. Today, I would like to discuss yet another side of global weather that does not get much attention.
In the posting on the meteorology blog, "The Atlas Barrier", we saw why there is a gap in the coastal barrier islands of the eastern and southern U.S. in the states of South Carolina and Georgia. It is because dust from North Africa is essential to provide condensation nuclei upon which water can condense to form the vast amount of dense cloud necessary for hurricanes. As the dust is swept out over the ocean by the east wind, it allows evaporated water from below to condense upon it. I identified the absence of significant barrier islands in those states as being due to the blocking of the wind-borne dust by the Atlas Mountains of Morocco.
This goes to show the vital role of dust in forming hurricanes. Air with the ordinary low level of dust cannot hold the tremendous volume of water necessary for hurricanes. That posting describes a hurricane as a self-sustaining circular storm. Hurricanes, which also go by other names such as "cyclone" and "typhoon", move generally westward because their spin, which they pick up from the spin of the earth, makes them semi-independent of the earth's gravity so that the earth rotates eastward under the storm.
It seems to me that dust is a forgotten side of extreme global weather. It is well-known that global warming creates wilder weather by causing more water to evaporate, but the air could not hold the water for long without abundant dust particles to serve as cloud condensation nuclei. The phenomenon of desertification, the increase of desert area, is pointed to as reducing arable land, but it also means more potential dust in the air to seed hurricanes if the prevailing winds are right to take the dust out to sea.
The way I see it, ground zero for global climate with regard to dust and extreme weather begins in Australia. Never mind the cricket rivalry between Australia and India, those two lands are linked not only by geology, they were once part of the same land mass, but by climate. It is dust from Australia, swept out to sea, that seeds the Monsoons and cyclones that afflict India and it's neighboring countries, in the same way that dust from North Africa is the foundation for the hurricanes that cross the Atlantic Ocean. The typhoons of the South China Sea are also seeded by dust from Australia. The prevailing winds over Australia carry it's loose dust northward, toward the equator.
Here is a map link: http://www.maps.google.com/
Australia is a dry continent, that is getting even dryer. There are areas which used to be farmed productively, which now cannot be farmed at all. The Government of Australia, along with that of China, is a leader in searching for ways to produce rain. This can only mean more dust becoming available to be swept out to sea by the wind.
When there is more dust in the air, it does not mean that more water will evaporate from the sea below. There is essentially no more water in the air, the dust just makes it more concentrated. This means that when the tremendous volumes of rain fall on the Indian Subcontinent, the air emerges dry as the prevailing wind at that latitude moves from the east. So that when the air gets downwind to the Arabian Peninsula, there is little or no water to provide rain.
If there was rain on the Arabian Peninsula, it would be lush and green with vegetation. Much of the water would reevaporate, or be transpired by the plants, and travel further west on the east wind to fall on the Sahara Desert of North Africa. Then if this area was lush and green, it would not be the source of dust that it is to seed the hurricanes that cross the Atlantic Ocean.
Can you now see how Australia is ground zero for so much of the global climate? it is the beginning of what I have termed "The Australia Sequence". If only we could make Australia lush and green, or even pave it over into a vast parking lot, so that it would not serve as a reservoir of dust, it would completely change the world.
(I am just using the parking lot as an illustration, the last thing that I would want to do would be to pave over Australia and upset Australian readers).
There would not be the dust to seed typhoons in the South China Sea. India, and neighboring countries, would not get the cyclones and extremely heavy rain. There would be water in the air to be carried along the east wind to fall as rain in Saudi Arabia. When that water reevaporated, it would carry further along the east wind to North Africa. The Sahara would become green, and would no longer be a source of dust to seed hurricanes heading for the western hemisphere.
What a better world that would be! This would most likely bring a potential increase in the world's food supply of between a quarter and a third, due to the vast increase in arable land.
If only we could make Australia into a lush and green place, it would cease to be a source of dust. India would get much milder rains, and the water that was left would fall on the Arabian Peninsula. Much of that would re-evaporate, or be transpired by plants, and would travel further downwind to fall on North Africa. This would, in turn, make what is now the Sahara Desert into a green place with thriving plants, meaning that North Africa would no longer act as a vast supplier of dust over the ocean to seed the hurricanes that afflict North America and the Caribbean.
It is easy to see why the east coast of South America is free of hurricanes, much unlike North America. Africa south of the Sahara is a land of expansive jungle and grassland. It is not dusty, and so does not supply the dust that would seed hurricanes that would move westward to strike South America. If only we could get Australia covered with plants, we would set a very beneficial sequence in motion.
By the way, this new plant life covering Australia, Arabia and, North Africa would absorb much of the world's carbon in the air that is the cause of global warming. We would definitely be "killing two birds with one stone", and really bettering the world in the process.
The main reason that Australia is so dry is that the winds, which might bring rain, are blocked by the Great Dividing Range of mountains, along the east coast of Australia. However, in east-central Australia lies the Great Artesian Basin. This is a vast area of low-lying land, which is Australia's main source of fresh water from wells. Much of the basin is below sea level, my world atlas has the surface of Lake Eyre North as 16 meters below sea level.
What if a canal could be dug, which would flood part of the Great Artesian Basin with sea water? This would form a vast, shallow salt-water reservoir west of the coastal mountains. This water would quickly re-evaporate to be carried westward by the prevailing winds.
Hopefully, it would fall as rain on the vast arid west of Australia. Plants would grow, and farming would thrive. The deserts would become grasslands and the continent would cease to be a source of a significant amount of dust to the region's large-scale weather patterns.
The area is sparsely populated anyway. This salt-water reservoir, covering hundreds of square kilometers would provide beaches and sites for resorts. Although it would not have the waves required for the Australian pastime of surfing. As fish-farming is becoming so popular across much of the world, the reservoir could be stocked with fish.
The reservoir would be shallow, and if Australians ever changed their minds about the project all that would be necessary is to close the canal and the water would not take long to evaporate.
The only drawback of the reservoir is that it would salinate the fresh water within it's shores. But this would be more than compensated for by the fresh water falling westward as rain.
This concerns the proposed project of digging a canal in Australia to flood part of the Great Artesian Basin with sea water. This is my idea to bring rain to Australia by bringing a large surface area of water west of the Great Dividing Range of mountains, since it is these mountains which block the east wind which would otherwise bring rain to this very dry land. This water would evaporate and fall as rain on the vast expanse of western Australia.
I believe that it is an accident of geology which prevented Australia from being the lush and green land that it could have been. This project could really change the world. China and Australia are already tied together economically. Australia is a source of raw materials for China, as well as a destination for Chinese tourists. Many signs in Australia are in Chinese.
Why not work together on this Project? There is a serious water shortage in parts of China. This project would result in milder rains that would carry much further inland in China, instead of the destructive typhoons along the coast. The governments of both countries have put a lot of effort into trying to induce rain artificially, why not try this idea?
It would be ideal if we could set up a parallel project to bring water to North Africa, the world's other great source of dust, as well. But there is no comparable area below sea level there which could be flooded. There is the Qattara Depression in Egypt's Western Desert, but I do not think that flooding it would have much effect on the rainfall.
No comments:
Post a Comment