This week in charts
Median monthly mortgage payments in America
Methane hunters: what explains the surge in the potent greenhouse gas?
Many researchers initially assumed the increase was linked to fossil fuel production. Methane is the primary ingredient in natural gas but is also produced by other human activities such as landfills, rice paddies and raising cattle.
In the past few years, however, that uptick has accelerated into a surge. The implications for global warming are immense: of the 1.1C increase in global temperatures since pre-industrial times, about a third can be attributed to methane. Atmospheric methane had its highest growth rate ever recorded by modern instruments in 2020, and then that record was broken again in 2021. Nobody knows exactly why.
Atmospheric methane (CH4 mole fraction, parts per billion)
“Methane is a very interesting type of greenhouse gas because it has so many kinds of sources and sinks that you have to keep track of,” says Dlugokencky. “You have to look at it like you are a detective trying to solve a criminal mystery, that is how I think of it.”
Global methane emissions and sinks estimate (2008-17 annual average, million tonnes)
Wetlands and cattle appear to be the biggest culprits, says Euan Nisbet, professor of earth sciences at Royal Holloway, University of London. “The biological sources are increasing faster,” he says. “The most intense growth seems to be coming from the tropics.” A global increase in cattle-raising, and in landfills, is also fuelling the growth in microbial emissions.
In an upcoming paper, Lan and Dlugokencky reach a similar conclusion: 85 per cent of the increase in atmospheric methane since 2007 is due to microbial sources. And about half of that is from the tropics.
"When people chase these popular investment themes, they are going to be disappointed," said Itzhak Ben-David, co-author of the study and professor of finance at The Ohio State University's Fisher College of Business.
"These hot-topic funds are based mostly on hype and tend to lose value relative to the general market almost as soon as they are launched."
"These specialized ETFs are all about areas hyped in social media and other platforms as the 'next big thing.' But by the time these ETFs are launched into the market and available to investors, it is already too late to make money," Ben-David said.
"Specialized ETFs are basically boiled down to a soundbite: 'You should invest in electric vehicles,' for example. That's it. Most of the investors in this don't know anything about the stocks in the ETF's portfolio, the fees, the price to earnings ratio. They just want to be part of the trend."
This week’s fun finds
But the data show that, when it comes to learning, handwriting definitely matters. Several studies have found that both children and adults learn and remember more when they write by hand. “It stimulates the brain in a very different way than a keyboard does,” says Audrey van der Meer, a neuropsychology professor in Norway whose research on the topic is widely cited.
The withered state of writing has begun to affect other lives too, like those of courtroom handwriting experts. “It’s a concern,” says Steve Cosslett, a British forensic document examiner who has given evidence in hundreds of court cases since he began his career at a Home Office forensic science laboratory in 1983. To check the authenticity of, say, a signature on a will, you need a number of genuine signatures by the writer. But these are harder to find now that people don’t sign things like cheques any more. “People can’t provide sufficient reference material,” he says.