Anthropogenic climate change is the consequence of human interference with the composition of the atmosphere. Since the beginning of the Industrial Revolution around 1750, humans have released large quantities of CO2 and other greenhouse gases into the atmosphere, mainly by burning fossil fuels, but also due to deforestation and land-use changes. These greenhouse gases (GHGs), which include water vapor (H2O), carbon dioxide (CO2), nitrous oxide (N2O), methane (CH4) and ozone (O3), warm the atmosphere by absorbing heat released from the Earth’s surface, inhibiting it from escaping into space, and re-radiating it.
The increase in CO2 concentrations is accompanied by rising surface temperatures. The year 2016 was the warmest year since records began in 1880, with global average surface temperatures about 0.94°C higher than the 20th century average (1901–2000). Most of the warming has occurred in recent years and, except for 1998, the ten warmest years on record occurred since 2001.
As the atmosphere warms, weather patterns change, ice sheets and glaciers melt, and sea level rises. Extreme weather events, such as heatwaves, storms and floods are now regularly on the news.
There’s once place that will – unnoticed by most people – experience the most pronounced changes: the Arctic. In the Arctic, warming is amplified when compared to lower latitude regions; a phenomenon called Arctic or polar amplification. The reason is positive feedback mechanisms that enhance warming. As the ice melts, less solar energy is reflected. The exposed darker water and land surfaces absorb more of the Sun’s energy than ice, warm up and melt even more ice. With less sea ice cover, more heat from the ocean escapes into the atmosphere. In a warmer climate, the spring melt will start earlier and snow will fall later in autumn due to longer summers. At the same time, less snow and ice will accumulate during shorter winter or melting will continue if temperatures are too high for snow and ice to build up. This winter (2016/2017), Arctic sea ice extent was the lowest since satellite records began in 1979.
Anthropogenic climate change is now measurable and observable, signalising that we have reached a boundary on this planet. However, despite our knowledge not much seems to change. But why do we not use climate change as an opportunity to create sustainable and fair societies that live within Earth’s ecological boundaries?