Happy birthday to #geochemist Charles David Keeling (1928 - 2005) whose decades long observations of CO2 in air samples from Mauna Loa Observatory were some of the 1st direct data to show the human contribution to greenhouse effect & global warming. The ‘Keeling Curve’ (in copper & red) shows both the seasonal variations (the wiggles) & the strong upward trend with time as the greenhouse gas built up in the atmosphere. 
The rate at which atmospheric CO2 is increasing is now outpacing the pathways set out by the Intergovernmental Panel on Climate Change (IPCC) that limit global warming to 1.5C.
The third working group report of the #IPCC’s sixth assessment report (#AR6), published in 2022, presented a set of seven “illustrative pathways” that highlight how different mitigation choices across major economic sectors translate into future #GreenhouseGas #emissions and global temperatures.
In the three most-ambitious pathways, #GlobalWarming has a 50% chance of either staying below 1.5C, or overshooting it by only 0.1C (for up to several decades) before then returning to below 1.5C.
Yet, not only are atmospheric #CO2 concentrations still rising, the rate of rise is #accelerating.
The build-up of CO2 in the #atmosphere has been monitored at the #MaunaLoa observatory in #Hawaii since 1958.
As illustrated by the iconic #KeelingCurve below, the increase has been accelerating over the decades (blue line) due to ongoing emissions of CO2 from burning #FossilFuels and changing land use.
So while the curve needs to rapidly bend in the other direction to hold warming to 1.5C (light red line), the rate of rising CO2 marches onwards and upwards.
https://www.carbonbrief.org/met-office-atmospheric-co2-rise-now-exceeding-ipcc-1-5c-pathways/
NOAA: "Carbon dioxide is accumulating in the atmosphere faster than ever — accelerating on a steep rise to levels far above any experienced during human existence, scientists from NOAA and the Scripps Institution of Oceanography offsite link at the University of California San Diego announced..."
"...“Over the past year, we’ve experienced the hottest year on record, the hottest ocean temperatures on record and a seemingly endless string of heat waves, droughts, floods, wildfires and storms,..."
https://www.noaa.gov/news-release/during-year-of-extremes-carbon-dioxide-levels-surge-faster-than-ever #keelingcurve #co2 #climateemergency #disasters
"The global average concentration of carbon dioxide in March this year was 4.7 parts per million (or ppm) higher than it it was in March last year, which is a record-breaking increase in CO2 levels over a 12-month period."
https://www.theguardian.com/environment/article/2024/may/09/carbon-dioxide-atmosphere-record?CMP=share_btn_url
#KeelingCurve
The eruption of #MaunaLoa interrupted the #KeelingCurve, the longest atmospheric #CO₂ time series in the world and the most iconic measurement in the environmental sciences.
Now, my workplace — University of Hawaiʻi at Mānoa — has helped set up a temporary CO₂ measurement on the nearby #MaunaKea to ensure that sampling of remote atmospheric CO₂ in the tropics could continue.
