In Half 1 of this three-part sequence specializing in a brand new report about local weather change in 2023, I described the relentless rise of greenhouse gases within the environment. Fairly than exhibiting indicators of leveling off — which should occur quickly if we’re to keep away from much more disruptive local weather modifications than we have already seen — they’re accumulating at an rising fee.
The truth is, 2023 noticed the fourth highest rise of atmospheric CO2 on file.
As I identified in Half 1, no facet of Earth’s climatic life assist system was spared final yr from the impression of the ever thickening blanket of heat-trapping gases we have thrown over the planet, in line with the State of the Local weather in 2023 report. That, in fact, consists of rising temperatures worldwide, which I deal with right here. (For hyperlinks to the opposite articles on this sequence, see the top of this story.)
To place it bluntly, international heating was utterly off the charts in 2023. In data relationship again so far as 1850, the annual international common floor temperature was by far the best ever noticed.
This map exhibits how common floor temperatures for 2023 diversified from the long-term imply. (Credit score: NOAA/NCEI)
Evaluation of seven separate datasets revealed that the worldwide floor temperature in 2023 was 0.55°C–0.60°C above the 1991–2020 common. This was the best worth on file, surpassing the earlier warmest yr on file, 2016, by a big margin.
The State of the Local weather evaluation additionally in contrast 2023’s international common temperature to what it was in pre-industrial occasions, earlier than humankind started spewing massive quantities of greenhouse gases into the environment. Based on the report, the worldwide floor temperature final yr was 1.35°C–1.54°C above that pre-industrial common.
“Dozens of nations reported file or near-record heat for the yr, together with China and continental Europe as an entire (warmest on file), India and Russia (second warmest), and Canada (third warmest),” the report states. Furthermore, “intense and widespread heatwaves had been reported around the globe.”
The bizarre international heating in 2023 wasn’t only a one-off. All seven datasets agree that 2015 via 2023 had been the 9 warmest years since international record-keeping started. And the warmth has gone on — and on: Each month via July of this yr has seen record-setting international temperatures, in line with NOAA.
Right here in 2024, final month was the warmest July globally in NOAA’s 175-year file. This marks the 14th consecutive month of record-high international temperatures, breaking the longest file heat streak within the trendy file. The earlier file international warmth streak was set from Could 2015 via Could 2016.
Ocean Heating
From 1971 via 2020, the seas have absorbed about 89 p.c of the warmth that has entered our planet’s local weather system because of our emissions of greenhouse gases. The State of the Local weather in 2023 report notes that the buildup of this warmth has been best on the floor — and it actually exhibits:
In 2023, international temperatures on the sea floor shattered the earlier file excessive. And record-breaking sea floor temperatures continued into 2024, solely exhibiting indicators of decline in latest weeks.
As an apart, that cooling pattern is more likely to proceed as a La Niña takes maintain. The local weather phenomenon is characterised by cooler than common sea floor temperatures within the tropical Pacific Ocean, and it tends to tamp down international averages.
However local weather fashions have been suggesting we’ll expertise a weaker and delayed onset of La Niña than beforehand thought.(For the newest on this, take a look at this put up on the ever-excellent ESNO weblog: August 2024 Outlook: A La Niña Watch within the Canine Days of Summer season.)
Again to 2023: The brand new report revealed {that a} surprising 94 p.c of the worldwide ocean floor skilled at the very least one marine warmth wave. These transient durations of exceptionally excessive ocean temperatures can super-charge tropical cyclones, whereas bleaching corals and harming ocean ecosystems, together with fisheries that hundreds of thousands of individuals around the globe rely on for meals.
Sometimes, at any given location, marine heatwaves are noticed about 10 p.c of the time. However in line with the report, in 2023 these occasions far exceeded what’s thought-about typical, “with record-breaking extremes (by way of space protection and depth) noticed everywhere in the world.”
In complete, 2023 noticed a file of 116 marine heatwave days throughout the yr, blowing away the earlier file of 86 days set in 1982.
These maps present the depth of warmth stress on corals throughout international coral bleaching occasions in 1998, 2010, 2014-2017, and 2023-2024. Warmth stress is ranked on a scale of 1 to five. (Credit score: NOAA)
Marine ecosystems have suffered significantly, as revealed by the severity and extent of coral bleaching. This could occur when corals are burdened a lot by heat sea temperatures that they expel the symbiotic algae residing with them, inflicting them to show ghostly white. Though bleached corals can survive, they’ll in the end die if the stress is simply too excessive and sustained.
Throughout 2023, bleaching of corals worldwide was significantly extreme — and it continued into this yr. Based on a latest report from NOAA, for the reason that starting of 2023 and persevering with at the very least via mid-Could 2024, mass coral bleaching had been confirmed in all ocean areas the place warm-water corals dwell, and in at the very least 62 international locations and territories worldwide.
Arising subsequent…
The unusually excessive diploma of world heating in 2023 was accompanied by myriad different impacts, together with accelerating ice loss, rising sea degree, modifications in cloudiness, decreased precipitation on common however heavier short-term deluges, and spreading drought. I deal with these impacts within the remaining installment of this sequence.
For Half 1 of the sequence, please go right here. And for Half three click on right here.
