Cause of global warming
Almost 100% of the observed temperature increase over the last 50 years,
are due to the increase in the atmosphere of greenhouse gas concentrations
like water vapour, carbon dioxide (CO2), methane and ozone.
Greenhouse gases are those gases that contribute to the greenhouse effect (see below).
The largest contributing source of greenhouse gas is
The burning of fossil fuels,
the largest contributing source of greenhouse gas,
led to the emission of carbon dioxide.
The greenhouse effect
When sunlight reaches Earth's surface,
some is absorbed and warms the earth,
and most of the rest is radiated back to the atmosphere
at a longer wavelength than the sun light.
Some of these longer wavelengths are absorbed by greenhouse gases in the atmosphere before they are lost to space.
The absorption of this longwave radiant energy warms the atmosphere.
These greenhouse gases act like a mirror and reflect back to the Earth some of the heat energy which would otherwise be lost to space.
The reflecting back of heat energy by the atmosphere is called the "greenhouse effect".
posted @ 5:11 AM |
