"Plunge is far faster than in Arctic and may lead to more global heating, say scientists" 'Precipitous' fall i...
Friday, August 30, 2019
A 2007 modeling study found that the loss of around 40% of the forest would reduce rainfall and extend the dry season in major parts of the Amazonia region, converting much of the eastern part into grassy plains where few trees can thrive.
The idea is that a certain level of deforestation will push the world’s largest rainforest to a tipping point, where spiraling feedback effects convert much of the forest into savannah. The massive greenhouse gas sponge, which holds around 17% of the world’s carbon trapped in vegetation on land, would suddenly become a major source of it.
That would be a monumental catastrophe. But how real of a danger is it?
Well, scientists can’t exactly say. Some models show the phenomenon, some don’t. Where some researchers detect a tipping point in the data—which technically means it would continue on its own even if the forces that first drove it fade away—others see merely progressive deterioration that could be halted. Still other studies have found such a phenomenon would most likely convert rainforest into seasonal forest, rather than savannah.
So what should we do in the face of this kind of scientific uncertainty? Like other climate tipping points, which are unpredictable and essentially irreversible once reached, we should err on the side of caution.
“Even if it’s a remote possibility, we cannot afford to ignore it,” says Jonathan Foley, executive director of Project Drawdown, a research group focused on decarbonization. “It would be absolutely catastrophic to the Earth’s carbon cycle, water cycle, climate, and biodiversity—not to mention the people who live there.”
Monday, August 26, 2019
Friday, August 23, 2019
In climate science there has been a tension between the drive towards consensus to support policy making versus exploratory speculation and research that pushes forward the knowledge frontier
Climate Change: What’s the Worst Case?
By Judith Curry
THE PERMIAN EXTINCTION
Thursday, August 22, 2019
Members cited concerns over changing party rules and opening the door for a flood of single-issue events
The Democratic National Committee has rejected mounting calls for a party-sponsored debate on the climate crisis, voting down a resolution that would have dedicated one of the 12 Democratic debates entirely to the issue.
Calls for a DNC-sanctioned climate debate have been building for months. In poll after poll, climate has been one of the most important issues to likely Democratic voters in the 2020 presidential election. But little time has been devoted to the topic in debates to date: a scant 15 minutes in the first set of debates, and just over 20 in the most recent two.
Party delegates are meeting this week in San Francisco to hear from 2020 candidates, hold fundraising events and tend to party business. But one of the gathering’s most urgent agenda items was to vote on competing resolutions to determine whether or not such an event would go ahead.
A committee rejected the resolution in a 17-to-8 vote. Photograph: Guy Bell/REX/Shutterstock
IMAGINE DNC ARE NOW DENIERS?
Posted by Unknown at 7:49:00 PM
Monday, August 19, 2019
Friday, August 2, 2019
"Extensive historical data shows recent extreme warming is unprecedented in past 2,000 years"
'No doubt left' about scientific consensus on global warming, say experts
The scientific consensus that humans are causing global warming is likely to have passed 99%, according to the lead author of the most authoritative study on the subject, and could rise further after separate research that clears up some of the remaining doubts.
Three studies published in Nature and Nature Geoscience use extensive historical data to show there has never been a period in the last 2,000 years when temperature changes have been as fast and extensive as in recent decades.
It had previously been thought that similarly dramatic peaks and troughs might have occurred in the past, including in periods dubbed the Little Ice Age and the Medieval Climate Anomaly. But the three studies use reconstructions based on 700 proxy records of temperature change, such as trees, ice and sediment, from all continents that indicate none of these shifts took place in more than half the globe at any one time.
LAST TIME PLANET GOT WARM