Climate changes science complex, effects clear
The surface temperature of venus is around 460 degrees C. In the case of Mars, the temperature can dip to as low as -140 degreeC. The reason : apart from the di right amount of CO2 in ts thstance factor, the amount of carbon dioxide present in the atmosphere plays a crucial role.
The atmosphere of Venus is comprised mostly of CO2 that prevents the heat from escaping, thus turning the planet into an oven. In the case of Mars, it lacks a thick atmosphere that can reatain heat.
Earth has the right amount of CO2 in the atmosphere that traps the right amount of heat from escaping thus making our planet neither extremely hot nor cold.
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Hence they are called carbon sinks. Ice reflects sunlight thus reducing the impact .Yet things are beginning to look grim.
There has been a sudden increase in the atmospheric CO2 since 2001. The natural sinks may be losing their ability to absorb CO2. A study of ocean data between 2000 and 2007 showed that ocean â€˜s ability to absorb CO2 has been reduced from 27 per cent to 24 percent.
The icesheets of Antartica and the Artica are unable to reflect the same quantum of sunlight as they are themselves prey to global warming and shrinking in size(melting). East Antartica, for instance has been losing at least 5 billiion tonnes of ice every year since 2006. According to recent observation of ice loss, Antartica could shrink by 33 percent by 2100, leading to a sea level rise of 1.4 metres.
Failing ocean sink
Algae and some marine organisms use C02 dissolved in water and turn them into organic compounds, thus locking up the greenhoue gas. But oceanâ€™s ability to act as a sink depends on how well it is able to sustain life.
As more and more C02 gets dissolved, the ocean will turn acidic; an acidic oceanâ€™s ability to absorb the greenhouse gas is compromised.
Acidic ocean also makes it difficult for calcium-shelled organisms to bulid shells.
In fact, acidic ocean can lead to leaching of shells and hence release of locked up carbon.
Plant growth myth
Increased CO2 levels can lead to faster plant growth (carbon fertilization), and in turn absorb more of the greenhouse gas. Studies have however found that higher CO2 levels will help only certain plant species.
For instance, while higher temperatures will boost plant growth in cooler regions, in the tropics they may actually impede growth.
A two-decade-long study undertaken in the rainforest plots in Panama and Malaysia concluded that more than 1 degree C in temperature can actually reduce tree growth by half.
But even the faster plant growth cannot removee the increasing levels of CO2. And plant growth can get negatively affected when a warmer earth increases evaporation resulting in drier soils. Food crops depend on many factors like soil type, climate, and moisture content soil. Any change in even one of them can affect a particular crop.
Some trees are beginning to move towards higher and less hot altitudes and some fishes unable to bear the increasingly hot waters of the tropics are moving north. Glaciers are retreating for kilometres up valley, the tropic is expanding , hurricanes are becoming more frequent, drought and floods are increasingly seen.
While afew warmer...