The following factors all
have an influence on Earth’s climate.
Some of these items cause global warming to increase more rapidly; others
may slow the process or even contribute to both effects.
Clouds
Clouds reflect sunlight, providing shade, which keeps Earth’s
surface cool. However, the water vapor within clouds is a greenhouse
gas. It traps heat in the atmosphere by bouncing energy back towards
the Earth, trapping heat. Scientists still disagree about whether the
net effect of cloud cover is to cool or warm the Earth. If global warming
continues, there will be an increased amount of clouds in our atmosphere,
which may help or hurt.
Forest Fires
Wildfires release carbon dioxide, a greenhouse gas, into the atmosphere.
By trapping heat, carbon dioxide contributes to the planet’s
warming. However, if a forest of similar size grows again, about
the same amount of carbon that was added to the atmosphere during
the fire will be removed. So, fires affect atmospheric CO2 in the
short term, but not on long timescales.
Volcanic Eruptions
Eruptions send ash particles into the stratosphere, blocking sunlight
from reaching the Earth’s surface and contribute to cooling.
Ash from volcanoes can have a worldwide effect, as ash in the stratosphere
is able to travel great distances. For example, Mount Pinatubo erupted
in 1990 sending enough ash into the atmosphere to lower Earth’s
average temperature for several years. However, volcanoes also release
carbon dioxide, which, over millions of years, causes warming.
Oceans
Heat is absorbed by ocean water and transported by currents worldwide.
Due to their ability to absorb and broadly distribute heat, the
oceans help to slow the process of temperature change in the
atmosphere.
People
Living things both produce and consume greenhouse gases, especially
carbon dioxide. Because human activities use huge quantities of fuels
that release carbon dioxide, currently far more greenhouse gases
are produced than consumed, contributing to global warming
Carbon dioxide:
Carbon, the building block of life, is released as carbon dioxide
gas when fossil fuels, the remains of ancient plant and animal bodies,
are burned. Carbon dioxide is taken out of the atmosphere by plants
during the process of photosynthesis.
Methane:
Methane gas is produced by microbes in natural wetlands and rice
paddies and by the digestive tracts of farm animals such as cattle
and sheep.
Nitrous oxide: This gas is produced when nitrate and ammonium in human-produced
fertilizers breakdown in the soil.
