"It is the largest increase we have ever seen in the 30 years we have had this network," Dr Oksana Tarasova, chief of WMO's global atmosphere watch programme, told BBC News.
"The largest increase was in the previous El Niño, in 1997-1998 and it was 2.7ppm and now it is 3.3ppm, it is also 50% higher than the average of the last ten years."
So, if some private entity just started seeding 'dead zones' of the ocean with iron, causing carbon-capturing algal blooms, would they face any legal sanction?
I know exactly 0 about maritime law other than 'Captains can perform weddings for some reason.'
A quick google shows something called the London Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter
But that's specifically talking about waste products and doesn't really address intentional atmospheric engineering.