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Trees and global climate change

March 19, 2010


By Trees For The Future Founded by Dave Deppner

December 23, 2009, 3:52pm

Climate change is one of the greatest environmental, economic and social threats facing the globe. The earth has been going through natural heating and cooling cycles, taking place over hundreds, often thousands, of years. Then, starting in the early years of the 19th century, the warming increased rapidly. The change began to accelerate during the Industrial Revolution, a time during the 1800s when new technology enabled industries to replace animal and human labor with machines driven by fossil fuels. These new machines revolutionized production and transportation, but at a significant cost to the environment.

Like wood and other organic fuels, fossil fuels – such as coal, gas and oil – are composed mostly of carbon. When burned, the carbon unites with oxygen and forms carbon dioxide (CO2).
As industries grew, and the use of fossil fuels increased, so did levels of carbon dioxide in the global atmosphere.

The use of fossil fuels has been increasing for almost 200 years. Now, more than ever, the atmosphere is filled with dangerously high levels of carbon dioxide. It is colorless and odorless, so we can’t see or smell it, but it spreads itself evenly throughout the world; air pollution does not respect international boundaries.

The Greenhouse Effect

Solar radiation from the sun, which we see as light and feel as heat, constantly shines on the earth. Some of the heat is absorbed and some is reflected. Carbon dioxide works like an invisible blanket that wraps around the earth, trapping the heat inside.

A greenhouse is a structure that is used in colder climates to grow plants, flowers, and vegetables. Even when outside temperatures drop below freezing, greenhouses are still warm enough inside to grow plants. Greenhouses are made of glass, which allows solar radiation to enter. The heat is trapped inside the greenhouse, allowing plants to grow all year round.

Increasing concentrations of carbon dioxide in the earth’s atmosphere insulate it like a greenhouse, leading to a gradual warming of the earth’s atmosphere. Carbon dioxide is the major greenhouse gas, but there are others as well, including methane and nitrous oxide.

Increasing Temperatures

Over the last 120 years, the average global temperature has increased by about 1.3 degrees C. The rate of increase is accelerating and that over this new century, the average temperature will increase by two additional degrees Celsius.

In recent years, we have seen record temperatures on every continent. Animals and insects are changing their migratory patterns. Invasive species and insects such as malaria-carrying mosquitoes are spreading into new territories. Glaciers in the arctic regions, on Mount Kilimanjaro in Kenya, Mount Fuji in Japan and throughout Europe, Asia, and the Americas, are melting, causing the world’s oceans to rise. People in small island nations in the Pacific Ocean have already been forced to abandon their homes.

As ocean temperatures increase, coral reefs die, hurricanes increase in frequency and strength, and weather patterns change. Droughts and floods have become more common than ever before.

The term ‘climate change’ refers to significant changes in the average weather, such as wind and rainfall, experienced in a region over a long period of time. The climate on earth has naturally undergone many changes in the past. The rate at which the climate has been changing over the past 200 years, however, has led to a consensus among scientists that this change is due to human activity. Global climate change is affecting all of us.

Atmospheric Levels of Carbon Can Be Brought Down

Through a natural process called photosynthesis, plants remove carbon dioxide from the atmosphere and release oxygen. They store this carbon in their leaves, branches, trunks and roots. Because trees grow faster in the tropics, they absorb more carbon than trees in temperate regions.

An average tree in the Trees for the Future’s program can remove about 23 kilos of carbon dioxide from the atmosphere annually. In agroforestry projects, where trees encourage the growth of other vegetation in their understory, the amount of carbon sequestration is further increased.

The Importance of the World’s Forests

Forests are critically important carbon warehouses that filter massive quantities of carbon from the atmosphere, trapping it in their biomass. The Food and Agriculture Organization of the United Nations estimates that the world’s forests store 283 gigatons (Gt) of carbon in their trunks and roots. Additionally, there is more carbon stored in the deadwood, leaves, and soils of forests than there is in the earth’s entire atmosphere (FAO, 2006).

Deforestation has caused the deaths of thousands upon thousands of people. Mudslides and floods that result from the loss of tree cover are happening more and more frequently.
Despite the common belief that clearing an area prevents the spread of malaria, it has now been shown that because forests also contain bats, birds, and other enemies of mosquitoes, deforestation actually increases the prevalence of malaria-carrying Anopheles mosquitoes.

The increased use of fossil fuels is only one part of the threat of Global Climate Change. With it, the earth is losing its forests at a rate of 14 million hectares every year (FAO, 2006). As lands are cleared they are also burned; releasing even more carbon into the atmosphere with fewer trees to remove it.
Introducing all this formerly-stored carbon into the atmosphere, with no corresponding mechanism to take it back out, has also contributed to the current high levels of CO2 in the atmosphere. Clearly, one part of the fight against climate change must include re-establishing global forest cover.

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