Earth’s atmosphere is a delicate balance of gases that make our planet habitable. A simple shift in this balance can be devastating.
Over the past century we’ve seen an exponential rise of Carbon Dioxide (C02) in our atmosphere from 0.028% to 0.04%. Whilst a seemingly small increase, this has contributed significantly to rising global temperatures.
C02 is a Greenhouse Gas made up of three loosely bound atoms (Carbon-Oxygen-Oxygen) within each molecule.
Sunlight enters the atmosphere as solar energy, hits the Earth’s surface and radiates back towards space as heat. The structure of each C02 molecule means heat is easily absorbed. The atmosphere then warms our planet.
This is in contrast to Nitrogen (78%) and Oxygen (21%) that have just two tightly bound atoms per molecule - making them poor absorbers of heat.
We do need a very small amount of C02 in our atmosphere as without it Earth would be inhospitably cold. However, there are natural sources of C02 that keep this healthy balance in check.
The concept of climate change can sometimes feel quite abstract. The term `climate` refers to long term weather patterns and is measured by meteorological variables like temperature, humidity, atmospheric pressure, wind, and precipitation.
Changing ratios of gas in our atmosphere, is causing our climate to shift to a new pattern.
This is consequential to every aspect of life on earth. But perhaps the largest, most direct indicator we have of this global shift is the swift retreat of our Arctic sea ice. Over the past 40 years, the Arctic’s summer ice cover has shrunk by more than half.
According to the National Snow and Ice Data Center, an organistion supporting research into our Earth's cryosphere - for every metric ton of C02 that a person directly or indirectly produces, 3 square meters of summer sea ice disappear from the Arctic.
Soon the Arctic will be seasonally ice-free, and we will be the cause.
Many species rely on this ice for hunting. A polar bear's home range is thought to be around a few hundred miles squared. Shrinking sea ice results in polar bears having to travel longer distances with longer fasting periods in search of food. Often causing starvation.
Models estimating future C02 levels are conservative. Temperatures must be kept below a 1.5°C rise, the internationally agreed target of 2°C is simply too high. Temperatures in 2019 are on avergae 1°C hotter that they should be and this is rising expotentially.