For most of human history, our activities have not affected Earth’s environment and geology; however, for the last century our economic actions, with their long-lived and durable effects, have shaped ecosystems. Past geological periods were named after the fossilised material in the deposited rock strata but the current period of Earth’s geological time has been informally dubbed the anthropocene since it is the first time that these processes are subject to human influence. This age is characterised by animal extinctions, habitat loss, chemical changes to oceans and soil and, in particular, climate change.
Although non-toxic and a natural product of respiration, carbon dioxide (CO2) is a gas that plays the biggest role in the heat balance of our planet. Like a blanket, CO2 prevents some of the Sun’s rays from escaping back into space; without it the world would be colder1, but too much CO2 and our world heats up due this greenhouse effect. Modern economies require energy and, over the last century, power has been provided through the burning of fossil fuels like coal, oil and gas; all non-renewable resources. In the past the focus was on their potential scarcity, however during past energy crises, at least one leader noted that this era would not end due to a lack of oil, but due to changes in technology.2 The “scarce resource” is the atmosphere’s ability to take up emissions without increasing the temperature of our ecosystem.
Carbon dioxide is measured in the atmosphere as “parts per million”(or ppm), where the current number near 400 ppm represents only 0.4% (= 400/1,000,000) of all air particles. Since human industry started and increased to scale a century ago, the ppm levels of CO2 have risen from about 300 to about 410 ppm. Although the level is small, the increased concentration of greenhouse gas has been enough to lift global temperatures by about 1 degree Celsius (almost 2 degrees) over the period.