the Environment: Greenhouse Effect
So what is this thing called the
The greenhouse effect is actually a natural thing. We need
it to keep the earth warm so that things can live and grow.
Without it, the earth would be too cold to support life.
Greenhouse gases (which include carbon dioxide and ozone) form
a blanket which stops the sun's heat from being reflected back
out into the atmosphere. It's a bit like the way the glass
ceilings and walls in Dad's greenhouse keep the plants
However, if these gases are allowed to increase to
dangerous levels, too much heat will be trapped, and our
climate will change. Unfortunately, this may be already
happening. The burning of fossil fuels, such as coal and
petroleum, the clearing of native forests for farms, and the
use of CFCs in air-conditioning and refrigerators, have all
contributed to the amount of carbon dioxide and ozone in the
atmosphere. How forests can help to slow down the
Forests can play a huge part in helping to reduce the
levels of carbon dioxide in our atmosphere. As they grow,
trees absorb carbon dioxide from the air and replace it with
oxygen. They store carbon in their trunks, branches and
leaves. And young trees are able to do this much better than
older, fully grown trees.
Young regrowth forests have a big appetite for carbon.
Growing trees is a great way of taking carbon out of the
atmosphere and storing it as wood. But wait - there's
Housing products made from wood need less energy to make
than other building materials, such as steel, concrete or
aluminium. When these materials are being manufactured, fossil
fuels are burnt, and lots of carbon dioxide is released into
the atmosphere. This contributes to the greenhouse effect.But the carbon that trees have absorbed from
the atmosphere gets stored in the wood. So long as the wood
isn't burnt, or allowed to decompose, the carbon will stay in
there for many generations.
An average-sized house with a wooden frame has removed 7.5
tonnes of carbon from the atmosphere, because the carbon is
now stored in the wood. However, a house with a steel frame
has actually added 2.9 tonnes of carbon to the atmosphere.
Timber is a more 'environmentally friendly' building
material than steel and other metal products, concrete or