Climate change is one of the greatest challenges we face in the 21st century.
To understand this challenge, one must recognize the difference between weather and climate. Weather is the state of the atmosphere in a given place and time that forecasters predict daily. Climate refers to average weather patterns in a specific region over many years. Although weather can vary greatly on a day-to-day basis, climate remains relatively stable over many years, changing very slowly or else dramatically due to cataclysmic events. Seemingly small changes in climate can have major impacts on all facets of life on Earth.
Weather and climate are both affected by molecules present in our atmosphere (a thin layer of gases that surrounds our earth). Many of these gases have come to be known as greenhouse gases (GHGs) and include water vapour, methane, ozone, nitrous oxide, carbon dioxide, and chlorofluorocarbons. GHGs are so named because they function analogously to glass in a greenhouse—allowing solar radiation to heat up the Earth and preventing this energy from escaping back through the atmosphere. Currently, the average global temperature is about 15oC but without the greenhouse effect it would most likely be closer to -18oC. The greenhouse effect is important because it makes the temperature of Earth suitable for life forms. Gases that comprise our atmosphere also help to protect us from the Sun's harmful UV radiation.
GHG's are naturally produced by animals, volcanoes, wetlands, forest fires, etc.; however, humans are generating more greenhouse gases than ever before. We are introducing chemicals to our atmosphere at rates much higher than what can be termed ‘normal' cyclical levels. For example, 85% of the primary energy driving global economies comes from the combustion of fossil fuels. This fossil fuel consumption accounts for 56.6% of all anthropogenic GHG emissions. In 2010, atmospheric concentrations of C2 were measured to be 390 ppm or 39% above preindustrial levels (IPCC, 2012). Although the Earth is well adapted to reducing GHG accumulation through carbon sinks (oceans, forests, etc.), we are currently generating more emissions than can be sequestered through natural processes. It might seem like it would be nice if our average temperature went up a few degrees; however this is not as simple as it sounds. Think about how mu8ch energy is required to heat up the entire Earth's atmosphere by one degree Celsius. It's A LOT! Adding this much heat to our Earth's surface will have serious repercussions: sea levels rising due to glacier and ice melt, oceanic acidification, less fresh water, seasons and habitats shifting or disappearing altogether, and extreme weather including flooding, droughts, and storms.
It is up to each and every one of us to work together to reduce our impact on the environment and prevent these trends from continuing.IPCC (2012). Renewable Energy Sources and Climate Change Mitigation: Special Report of the Intergovernmental Panel on Climate Change. New York: Cambridge University Press.