Explain how rain forest are important in regulating the world climate?

Question

Explain how rain forest are important in regulating the world climate?

Answer 1

the most important thing they do is absorbing carbon dioxide from the atmosphere. as carbon dioxide is a greenhouse gas, decreasing its concentration in the atmosphere slows down global warming.

Answer 2

Rain forests don't "regulate" world climate. Rather, they engage in important feedback mechanisms with the carbon cycle, climate, and human activity. Vegetation growth responds positively to increased CO2 (Piao et al 2001) and also to increases in precip & temperature (Cramer et al 2001). Growth has been generally increasing for the past 30 years (Cramer et al, Kaplan et al 2005). However, the future is uncertain, as there are upward limits imposed by nutrient availability (esp nitrogen) and by plant physiology (after a certain point, production decreases as CO2, temp increase) (Oke, 1987). Soil moisture is also an important limiting factor (Lucht et al 2002).

There is a great deal of research being conducted right now in the biogeochemistry-climate modeling community to answer your exact question. The current thought is that vegetation growth will help curb global warming for the next 20-50 years, though not nearly enough to mitigate the extreme changes we're expecting (it won't stop the rapid melting of ice sheets, for instance). In 50 or so years, the carbon sink could become a carbon source- and this is predicted by models that DON'T include land use, such as rampant slash and burn agriculture.

Rain forests are most important for regulating regional climate, because their presence shifts the radiation budget towards latent heat flux (Oke 1987). So forested regions will tend to dry out before they heat up. Evaporation and precip in the tropics will also likely increase.

Sorry if this is way more science than you wanted. But as a climate scientist whose research focuses on terrestrial biosphere response to variable climate - well, I just couldn't resist!