The amount of heat trapped in the troposphere determines the temperature on earth. The amount of heat in the troposphere depends on concentrations of atmospheric greenhouse gasses and the amount of time these gasses remain in the atmosphere. Since the industrial revolution in began, human processes have been causing emissions of greenhouse gasses, such as CFC's and carbon dioxide. This has caused an environmental problem: the amounts of greenhouse gasses grew so extensively, that the earth's climate is changing because the temperatures are rising.
This unnatural addition to the greenhouse effect is known as global warming. It is suspected that global warming may cause increases in storm activity, Melting of ice caps on the poles, which will cause flooding of the inhabited continents, and other environmental problems. Together with hydrogen , carbon dioxide is the main greenhouse gas. However, hydrogen is not emitted during industrial processes.
Humans do not contribute to the hydrogen amount in the air, this is only changing naturally during the hydrological cycle , and as a result it is not a cause of global warming. Carbon dioxide emissions have risen from ppm in to ppm in the s. In the previous paragraph various human activities that contribute to the emission of carbon dioxide gas have been mentioned. Most carbon dioxide emissions derive from industrial processes in developed countries, such as in the United States and in Europe.
However, carbon dioxide emissions from developing countries are rising. In this century, carbon dioxide emissions are expected to double and they are expected to continue to rise and cause problems after that. Carbon dioxide remains in the troposphere about fifty up to two hundred years. The first person who predicted that emissions of carbon dioxide from the burning of fossil fuels and other burning processes would cause global warming was Svante Arrhenius, who published the paper "On the influence of carbonic acid in the air upon the temperature of the ground" in In the beginning of the it was confirmed that atmospheric carbon dioxide was actually increasing.
In the late s when highly accurate measurement techniques were developed, even more confirmation was found. By the s, the global warming theory was widely accepted, although not by everyone. Whether global warming is truly caused by increasing carbon dioxide in the atmosphere, is still debated. The Kyoto treaty. World leaders gathered in Kyoto, Japan, in December to consider a world treaty restricting emissions of greenhouse gases, mainly of carbon dioxide, that are thought to cause global warming.
Unfortunately, while the Kyoto treaties have worked for a while America is now trying to evade them. Carbon dioxide: Air pollution. Since the beginning of the last century, photosynthesis on a global scale has increased in nearly constant proportion to the rise in atmospheric carbon dioxide. Most of the rest is attributed to a longer growing season in the rapidly warming boreal forest and Arctic. Plants and ecosystems use the sugar both as an energy source and as the basic building block for growth.
When the concentration of carbon dioxide in the air outside a plant leaf goes up, it can be taken up faster, super-charging the rate of photosynthesis. More carbon dioxide also means water savings for plants. More carbon dioxide available means pores on the surface of plant leaves regulating evaporation called the stomata can close slightly.
They still absorb the same amount or more of carbon dioxide, but lose less water. The resulting water savings can benefit vegetation in semi-arid landscapes that dominate much of Australia. We saw this happen in a study, which analysed satellite data measuring changes in the overall greenness of Australia. This suggests water efficiency of plants increases in a carbon dioxide-richer world.
Scientists have also looked specifically at the effects of rising CO 2 on agricultural plants and found a fertilization effect. She and other experts note there is an exception for certain types of plants such as corn, which access CO 2 for photosynthesis in a unique way.
Doubling CO 2 from pre-industrial levels, she adds, does boost the productivity of crops like wheat by some A lack of nitrogen or other nutrients does not affect agricultural plants as much as wild ones, thanks to fertilizer.
Both of those figures are in addition to the number of people who already have such a shortfall. A total of 1. But that is not how the world—or its climate—works. Already a subscriber? Sign in. Thanks for reading Scientific American.
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