If you are reading this, it's probably no surprise to you that we are in the midst of a climate crisis. We keep hearing about the rapidly developing evidence for how global warming threatens our ecosystems and life as we know it. In this introduction, we address some fundamentals that we believe everyone should be aware of with regards to the current situation. We try to keep it simple, but for more in-depth reading, we highly recommend the work of the World Economic Forum, Breakthrough Energy, Pale Blue Dot’s public research, and The 6th IPCC assessment report.

If weather is your mood, climate is your personality

You might have heard people confusing weather with climate change, maybe even joking about how there is no climate change in sight (like during the 2023 spring in Sweden…). Well, while weather always changes from year to year, with some years being colder and others warmer, climate change is something else. It refers to long-term shifts in temperatures and weather patterns. Such shifts can be natural, due to changes in the sun's activity or large volcanic eruptions. But since the 1800s, human activities have been the main driver of climate change, primarily due to the burning of fossil fuels like coal, oil, and gas.

This is because when fossil fuels burn, they release greenhouse gases, mostly carbon dioxide (CO2). These greenhouse gas emissions then act like a blanket wrapped around the Earth, trapping the sun's heat, leading to rising temperatures.

The world is now about 1.1C warmer than it was in the 19th Century, and the amount of CO2 in the atmosphere has risen by 50%. Among other things, this leads to more extreme weather events across the globe, threatening lives and livelihoods.

Temperature changes from mid-20th century to 2020

Source: NASA Goddard Institute for Space Studies

Main causes

The main greenhouse gases responsible for climate change are carbon dioxide (CO2) and methane (CH4). CO2 is generated by burning gasoline for transportation or coal for heating buildings. Clearing land and deforestation also release carbon dioxide. CH4 emissions, on the other hand, mainly come from agriculture, oil and gas operations. To facilitate discussions, most people use “CO2 equivalents” (CO2e) to measure greenhouse gas emissions. CO2e refers to the number of metric tons of CO2 emissions with the same global warming potential as one metric ton of another greenhouse gas.

The five main sources of greenhouse gas emissions are electricity, transportation, manufacturing, buildings, and agriculture.

Five main emission sectors

Source: Breakthrough Energy