Climate change, also called global warming, refers to the rise in average surface temperatures on Earth. Other planets in our solar system are either far too hot or far too cold, Earth, on the other hand, has stable temperatures due to the thin layer of gases that blanket and protect the planet.
There is an overwhelming scientific consensus that maintains that climate change is due to humans changing the atmosphere primarily through the human use of fossil fuels, which releases carbon dioxide and other greenhouse gases into the air. These gases trap heat within the atmosphere, which can have a range of effects on ecosystems, including rising sea levels, severe weather events, and droughts that render landscapes more susceptible to wildfires.
Causes of Climate Change
Rising levels of carbon dioxide and other gases, such as methane, in the atmosphere, create a ‘greenhouse effect’, trapping the Sun’s energy and causing the Earth, and in particular the oceans, to warm. Heating of the oceans accounts for over nine-tenths of the trapped energy. Scientists have known about this greenhouse effect since the 19th Century.
So what is the Green House effect then?
The greenhouse effect is a natural process that warms the Earth’s surface and is essential to life on Earth. The Earth is warmed by a combination of incoming and outgoing radiation. The incoming solar energy has a very short wavelength and passes through the atmospheric gases unaffected to reach the earth’s surface, approximately 70 percent of the energy stays on the planet, absorbed by land, oceans, plants and other things. The other 30 percent is reflected back into space by the outer atmosphere and other reflective surfaces such as clouds and snow fields.
But even the 70 percent that gets through doesn’t stay on earth forever (otherwise the Earth would become too hot). The Earth’s oceans and land masses eventually radiate heat back out in the form of infrared radiation. Some of this heat makes it back into space. The rest of it ends up getting absorbed when it hits certain things in the atmosphere, such as carbon dioxide, methane gas, and water vapor. After these components in our atmosphere absorb all this heat, they emit energy (also in the form of heat). The heat that doesn’t make it out through Earth’s atmosphere keeps the planet warmer than it is in outer space because more energy is coming in through the atmosphere than is going out. This is all part of the greenhouse effect that keeps the Earth warm.
It’s defined as the greenhouse effect because it works in much the same way as a greenhouse’s glass walls. Incoming ultraviolet light can pass easily through greenhouse glass and then be absorbed by the plants inside as heat. However, the outgoing radiation is much weaker and can’t get back through the glass walls. So it’s trapped inside, creating a warm atmosphere for the plants.
So how does the Green House effect, affect climate change?
As we discovered, green house gases occur naturally in the environment and keeping the outgoing and incoming radiation roughly equal is a very delicate balancing act. Humans are changing the strength of the greenhouse effect by increasing the proportion of greenhouse gases in the air. The main gases that are termed ‘greenhouse’ gases (GHG’s) are: Ozone, Carbon dioxide, Nitrous oxide, Water vapor and Methane. All of these are naturally occurring. With the increase of GHG’s in the atmosphere, more heat gets trapped, which increases the Earth’s surface temperature and that results in global warming.
What are we doing to increase the green house gases?
Burning Fossil Fuels
Scientists are particularly concerned about the impact carbon dioxide is having on the greenhouse effect and thus climate change. Burning fossil fuels puts carbon into the atmosphere. Other smaller sources include industrial processes such as cement manufacture and natural gas flaring. Burning changes the state of stored organic carbon from a liquid (e.g. oil) or solid (e.g. coal/wood) into a gas (carbon dioxide) which is then released into the atmosphere.
Vegetation absorbs carbon dioxide from the atmosphere during the process of photosynthesis, converting this to carbon which is stored within all plants (i.e it is a carbon sink). When vegetation is burned, this organic carbon is released into the atmosphere in the form of carbon dioxide, and in so doing becomes a carbon source rather than a carbon sink.
Nitrous oxide is a potent greenhouse gas that is released primarily by fertilizers used in agriculture and landscaping, but also during the burning of fossil fuels and other organic matter.
An increase in Methane emmissions
While methane doesn’t linger as long in the atmosphere as carbon dioxide, it is initially far more devastating to the climate because of how effectively it absorbs heat. In the first two decades after its release, methane is 84 times more potent than carbon dioxide. Both types of emissions must be addressed if we want to effectively reduce the impact of climate change.
There are both natural and human sources of methane emissions. The main natural sources include wetlands, termites and the oceans. Natural sources create 36% of methane emissions. Human sources include landfills and livestock farming. But the most important source being the production, transportation and use of fossil fuels. Human-related sources create the majority of methane emissions, accounting for 64% of the total
Chlorofluorocarbons (CFCs) are long-lasting greenhouse gases that also destroy the ozone layer. CFCs do not occur naturally in the atmosphere – they are synthetic compounds that only originate from human sources, including: aerosols, foaming agents, refrigerants, and other industrial applications.