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Complicating Factors

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.