I saw a Tweet recently that asked, “So what caused climate to change before humans were around?” It was clearly an ill-posed question with the intent of undermining the notion that humans can contribute to climate change. After my head stopped hurting from consuming that question, the first thing that came to mind is, “Gee, what caused grass to grow before fertilizer and big box hardware stores?” Hopefully, you get my point. Anyhow, climate has always changed naturally, and anthropogenic activities are amplifying those changes now. At roughly the halfway point of 2023, three things have caught the eye of climate scientists and not in a good way.
The global 2-meter temperature anomalies
The 2-meter temperatures are simply those measured at that height above the ground. It is a pretty standard metric within meteorology and climatology. Anomalies represent differences from an established climatological baseline. Brian McNoldy is an atmospheric scientist at the University of Miami. His viral Tweet below has been viewed over one million times.
I will deal with the 2-meter temperatures first. The black line in the graphic on the left represents the year 2023. Right now, it is trending well above any other years since recordkeeping began. Why so? It certainly not an “either/or” answer as some people try to make it. There is clearly a strong influence of anthropogenic climate change, but there is likely some natural variability associated with complicated dynamics and modes within the atmosphere-ocean system. For example, we have gradually been shifting into an El Niño pattern, which will likely continue to influence global temperatures.
When asked by a follower if we are at a point of extinction, McNoldy said, “Well, I don’t think it’s anything that extreme immediately….an anomaly for sure, and record-shattering. These are global averages, lots of ups and downs in the mix… just mostly ups.” Retired math professor Eliot Jacobson’s Tweet provides additional context below. Using statistic, he backs out the probabilities of this happening and arrives at a 1 in 1.3 million chance of occurrence.
The sea surface temperatures are very warm, too
The other part of Mcnoldy’s tweet illustrated that sea surface temperatures (SST) are running pretty warm too. The map below shows current SST anomalies around the globe. Dr. Jens Terhaar is an ocean scientist at Woods Hole Oceanographic Institute. In late April, he tweeted, “While the recent SST anomaly is terrifying, it is not unexpected. CMIP6 models predicted the monthly 0.7°C anomaly (comp. to 1982-2011) to be reached between 2017 & 2040. This wouldn’t have happened without climate change, we are in a new climate state, extremes are the new normal.” Warm ocean temperatures have implications for hurricane season, ocean state, and global weather patterns.
The trend in atmospheric carbon dioxide
On June 5th, the National Oceanic and Atmospheric Administration (NOAA) reported that carbon dioxide levels measured at its facility at Mauna Loa, Hawaii reached a peak of 424 parts per million (ppm) this May. The NOAA press release said, “That is an increase of 3.0 ppm over May 2022, and represents the fourth-largest annual increases in the peak of the Keeling Curve in NOAA’s record.” Scientists at Scripps, who run a different data record, confirmed similar numbers. NOAA went on to say, “Carbon dioxide levels are now more than 50% higher than they were before the onset of the industrial era.” The agency also explained in the press release how their analyses accounted for recent volcanic activity in the region.
NOAA Administrator Rick Spinrad captured the essence of the “So what?” in his statement. He stated,”Every year we see carbon dioxide levels in our atmosphere increase as a direct result of human activity….we see the impacts of climate change in the heat waves, droughts, flooding, wildfires and storms happening all around us.”