humid

Both regions are also relatively humid, which the researchers suggest may have helped protect artifacts placed inside the tombs.

"For sure, that would definitely help," said James, "later kick-offs when it's not so hot and humid. That would definitely help."

BELÉM, Brazil—This Amazonian city is hot, humid and hard to get to—perhaps not an obvious setting for a major international event.

Starting Monday, the 50,000 participants of COP30 will instead feel the heavy, humid air of the Amazon rainforest in Belem, Brazil, where they face the daunting task of keeping global climate cooperation from collapsing.

That happens when a sudden updraft in humid, moist air leads to a heavy and localised burst of rain.