How is the impact of climate change measured?
For this answer, we’ll cite a great article from BBC News, which points to five key indicators used to assess the gravity of climate change.


Carbon dioxide (CO2) is first. We are at 420 ppm (parts per million) now (yearly average). Since the 1970s we’ve added 100 ppm, roughly two points per year. Measuring the concentration of CO2 in the atmosphere is one way scientists track human impact on the climate. We can only emit 350 billion tons of CO2 to have a chance at regeneration. Currently, there is no silver bullet, like carbon removal. What’s really important about CO2 is that reducing our emissions is, while difficult, within our reach should we collectively elect to create change. 


Heat is next. We all notice this one, with warmer summers and less predictable winters. Heat is measured globally, on land, air and in the oceans. If you fish or raft, then perhaps you’ve noticed a difference in river flow and water temperature than in previous years.  Since scientists started tracking climate, 2022 was the warmest year on record, with the ten warmest years all since 2010. The oceans are also at the warmest temperatures ever recorded.


Places that are normally mild, like western Montana and the Pacific Northwest, suffer more from the increased heat, simply because our ecosystems are not built for it. It translates to species loss since many of our flora and fauna are not prepared for sustained or intense heat. 


Scientists also keep an eye on global ice reserves to see how much warming is impacting sea levels. We need ice on both the North and South Pole to stabilize global weather patterns. Climate change causes ice loss at the Poles at rates higher than in other climates. Arctic sea ice is thinner than normal, as is that around Antarctica. Less ice means more heat is absorbed directly onto the land and water, melting any remaining ice. As a result, Antarctica is losing ice at 150 billion tonnes per year. Ice melt is directly correlated to sea level changes; many countries and coastal cities are threatened. 


Like ice, permafrost is also a critical stabilizing force. Permafrost is ground that is consistently frozen.  Ground masses like Canada, Greenland and Siberia hold twice as many greenhouse gases as the air. While these are frozen, the gases (such as methane and CO2) are trapped. When the ground thaws, they are released into the atmosphere.


The final element is forests. They act, when they are an intact ecosystem, as a carbon storage, capturing pollutants from the air (45% of the global total) and storing them below ground. When destroyed - through deforestation or wildfires - carbon is released and temperatures rise. 


Every indicator, alone, is concerning. Taken together they point to an undeniable pattern of climate change and the human-caused impact on our planet.
470 words