Multiple leading scientific bodies, including the IPCC, NOAA, and the European Copernicus program, all confirm that 2023 was the hottest year on record.
According to Copernicus Climate Change Service, the primary driver of the record heat was an ongoing rise in atmospheric greenhouse gases, predominantly carbon dioxide from fossil fuel consumption. According to the National Oceanic and Atmospheric Administration (NOAA), at Climate.gov, 2023 saw atmospheric carbon dioxide reach its highest recorded concentration in history, 424.0 parts per million. Observations for 2023 were above the central estimate of climate model projections from the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report but still within the upper limit of the model range. Translated, this means the climate is worsening faster than expected.
In addition, a strong El Niño coincided with the high greenhouse gas levels, amplifying the warming effect. El Niño disrupts natural ocean circulation patterns, bringing warmer surface waters to the Pacific and influencing global temperature patterns.
2023 witnessed six record-breaking months and two record-breaking seasons in terms of global average temperatures. According to the BBC, almost every day from July onward saw a new global air temperature high for the time of year. According to Carbon Brief, it was the warmest year on record in 77 countries, from China to Germany to Mexico, affecting 2.3 billion people.
Global surface temperatures (land and ocean combined) in 2023 were 1.48 degrees Celsius warmer than the preindustrial average (1850-1900), exceeding the previous record set in 2016 by 0.17 C, according to the Copernicus Climate Change Service. It was the first year in recorded history where every day exceeded 1 degree above the preindustrial level. It was the first year the global average land temperature was more than 2 degrees above preindustrial levels.
In addition, ocean temperatures shattered records in 2023, with the highest average sea surface temperatures ever observed, according to the National Oceanic and Atmospheric Administration. It was the first year that global average ocean surface temperatures exceeded 1 degree compared to preindustrial levels. Warming oceans exacerbate sea level rise, intensify storms, and disrupt marine ecosystems. Here are two data points:
First, in 2023, sea levels reached new record highs, an alarming trend given the number of people who live on coasts. Millions will be displaced if this trend continues, causing massive migration issues.
Second, many scientists believe the vast majority of coral reefs will not survive when the average ocean temperature exceeds 1.5 degrees above the preindustrial average, a temperature we are barreling toward. If this happens, one-third of the ocean species will go extinct. In reality, a significant number of reefs and species have already died out, all because of anthropogenic climate change.
As many of you have seen and commented on, the record heat contributed to increased heat waves, droughts, wildfires, and other extreme weather events across the globe. For example, the Canadian wildfires in 2023 were unprecedented, and most scientists expect severe wildfires to continue well into the future during an ever-increasing wildfire season. According to Copernicus, Canadian wildfires released 480 megatons of carbon dioxide in 2023, almost five times the average for the past 20 years and roughly equivalent to the annual emissions of 100 coal-fired power plants.
All of this is to say we are in severe trouble from a climate perspective, as I’ve said many times in this column. Humanity must act quickly and decisively during these next three decades to change this trend. What can we do in Harvard? Next time, I’ll cover how anyone in town who chooses to can become a climate activist, something I believe many should consider if we want to protect the planet for future generations.
Until then, I’ll leave you with a bit of the conversation I recently had with a friend learning about the climate crisis. He asked a great question during our talk––why do climate scientists often talk about climate change and climate activists often talk about the climate crisis? He wondered if the climate activists were overstating the problem. Hopefully, you’ll agree climate activists are not overstating the problem based on what I’ve shown in this and past columns, but to drive home all my earlier points, here’s how I answered him.
Climate scientists talk about why anthropogenic climate change is happening and what it will mean to the world if we don’t act. They have been doing this since at least 1989, and for most of the time since then, world leaders have ignored them. It’s this lack of action that has made it a crisis. Think of a big bus carrying the world’s entire population racing toward a cliff. Because it’s a gigantic bus, and it’s going pretty fast, it’s going to take some time to slow it down, change direction, and avert a catastrophe. Currently, most scientists believe it will take decades if humanity fully commits to a solution.
If the bus drivers, the world leaders in this analogy, had started slowing down in 1989, we would have had plenty of time to change course, and we wouldn’t be in a climate crisis now. We would have solved the problem much like we solved the ozone problem. Instead, the bus drivers sped up by lots. So, now, while it’s still possible to stop the bus in time, we have a lot less runway to do so, and there is no margin for error. In fact, a great deal of avoidable damage has already been done, with 2023 the latest proof point. That’s a crisis in my book. Hopefully, it is in yours, too.
Rich Marcello is a novelist and a member of the Climate Initiative Committee. In writing his latest novel, “The Means of Keeping,” he spent several years researching the climate crisis.
