The Intergovernmental Panel on Climate Change (IPCC) does not mince its words when describing the disastrous effect that humans are having on the planet. “It is unequivocal that human influence has warmed the atmosphere, ocean, and land,” reads its latest report.
From heat waves and wildfires to downpours and flooding, 2023 has given us a taste of the impacts we can expect over the coming decades and centuries. In short, it’s not good news. Without very significant reductions in greenhouse gases—beginning immediately—it is very likely that global surface temperatures will exceed the 1.5 degrees Celsius threshold set in the 2015 Paris climate agreement.
Even if we do curtail emissions, sea levels will almost certainly continue to rise throughout this century and may continue to rise for centuries or millennia beyond that. Extreme weather events have become more frequent since 1950 and will become more frequent and more severe as global temperatures increase.
The message could not be clearer: We need to do everything we can to reduce our greenhouse gas emissions right now. Unless we take major action to stop emissions, we’re facing an Earth that is hotter, plagued by more extreme weather, and less hospitable than the already-warmed planet we have today. Here’s everything you need to know about where we are with the climate crisis.
1. There’s more carbon dioxide in our atmosphere than at any time in human history
The Mauna Loa observatory in Hawaii has been tracking Earth’s atmospheric concentration of CO2 since the late 1950s. In 2022, the global average concentration it recorded was 417.06 parts per million (ppm). Preindustrial levels were 278 ppm, which means that humans are halfway to doubling the concentration of CO2 in the atmosphere compared to the period between 1750 and 1800.
CO2 concentrations fluctuate with the seasons, while the speed at which they increase yearly is affected by human behavior. For example, the rising concentration of CO2 in the atmosphere slowed during the early stages of the pandemic when emissions fell, but then rose steeply in 2021 as the world reopened. The annual rise in emissions and atmospheric concentration of CO2 has since slowed down again.
The global average CO2 concentration for 2023 is predicted to be 419.2 ppm. The last time Earth’s atmosphere contained this much CO2 was more than 3 million years ago, when sea levels were several meters higher and trees grew at the south pole.
2. We’re accelerating down the path to exceeding 1.5 degrees Celsius of warming
In 2015, the nations behind the Paris Agreement set an ambitious target for keeping global warming below 1.5 degrees Celsius. The latest IPCC report spells out just how difficult it will be for the world to stay under that limit unless we drastically slash emissions now. The report models five different future emission scenarios—from very high emissions to very low emissions—and in each scenario global surfaces are expected to hit at least 1.5 degrees.