By Barry Lough of www.stuffintheair.com
What is the right climate for tropical rainforest areas? A tropical rainforest climate has uninterrupted warm temperatures, elevated humidity, with lots of rain. Gotta be paradise, right? Not necessarily, but definitely sounds like one of these rainforests.
How warm is it? Tropical air masses have a lot less temperature changes in than those seen in temperate zones. For most areas the temperatures hang around the 25 to 30 degrees Celsius range, with little seasonal variation. There is not too much diurnal change either. That is, it does not drop off sharply at night.
Why is it not hotter? A thick forest-canopy keeps it quite dark at ground level and most incoming solar radiation, insolation, does not make it to the soil. Additionally, a presence of high moisture levels results in evapo-transpiration which transports excess heat from the vicinity.
This special micro-climate for tropical rainforest soils starts with a state of darkness and coolness that keeps floor-level vegetation from growing in too thick, like the typical jungles seen in movies. Vines may climb trees to reach the sunlight, but other low-level vegetation remains quite sparse.
It's not just about temperature, though. The forests have a tremendous amount of precipitation and, consequently, many-many species of tropical rainforest plants and animals. The first thing a visitor sees is the thick canopy of tall trees.
Other influences can cause great variety in these regions. For example, lots of mountains in Ecuador results in ecological diversity. They have multiple microclimates and a plethora of unique organisms for each.
Rainforests can have a wet and dry season, though. But they're called rain forests for a reason. These climatological regions lie within the inter-tropical convergence zone.
The what? This climate for tropical rainforest precipitation lies in a region of quasi-stationary low pressure areas with nearly constant rain. Some areas get over 4000 mm of rain per year, while locations with a dry season may get half of that or less.
So then, where do we find these tropical rainforests? Mostly near the equator. Broad areas like Central and South America, southeast Asia, central Africa, northern Australia, and several tropical islands in the Caribbean and equatorial Pacific.
Some scientists have stated that elevated atmospheric carbon dioxide will cause a dramatic increase in the average surface temperatures of the earth, including the climate for tropical rainforest biomes. We call that global warming.
When it comes to carbon dioxide, the forest giveth, and the forest taketh away. Scientifically we can say that some forested regions emit CO2 into the air while others sequester it instead, and that the net contribution is smaller than you might imagine.
Now how does global warming affect the rain forest climate? Increasing carbon dioxide levels correlate with deforestation. But that is all that can really be said for sure. As some countries have lost more than fifty percent of their forest cover, we may discover some alarming empirical results in the near future.
Deforestation also leaves the region with its own modified climate for tropical rainforest growth. And it may be problematic. Increased soil erosion, species extinction, heightened pollution, reduced oxygen supply and possibly a redistribution of the world's precipitation may make it impossible for the forest to come back.
They are something worth preserving.