We’ve Grossly Underestimated How Much Cow Farts Are Contributing to Global Warming

Original Article

By George Dvorsky

Image: AP

A new NASA-sponsored study shows that global methane emissions produced by livestock are 11 percent higher than estimates made last decade. Because methane is a particularly nasty greenhouse gas, the new finding means it’s going to be even tougher to combat climate change than we realized.

We’ve known for quite some time that greenhouse gases produced by cattle, sheep, and pigs are a significant contributor to global warming, but the new research, published in Carbon Balance and Management, shows it’s worse than we thought. Revised figures of methane produced by livestock in 2011 were 11 percent higher than estimates made in 2006 by the Intergovernmental Panel on Climate Change (IPCC)—a now out-of-date estimate.

It’s hard to believe that belches, farts, and poop from livestock could have any kind of global atmospheric effect, but it’s an issue of scale, and the nature of methane itself.

There are approximately 1.5 billion cows on the planet, each and every one of them expelling upwards of 30 to 50 gallons of methane each day. We typically think of farts as being the culprit, but belches are actually the primary source of cattle-produced methane, accounting for 95 percent of the problematic greenhouse gas.

And problematic it is. Methane is about 30 times more efficient at trapping the Sun’s radiative heat than carbon dioxide over a timescale of about a century. There may be more CO2 in the atmosphere than methane, but by unit, it’s the more destructive greenhouse gas. Both NASA’s Carbon Monitoring System research initiative and the Joint Global Change Research Institute (JGCRI) contributed to the study.

Wolf’s team re-evaluated the data used to produce the IPCC 2006 methane emissions estimates. The prior estimates were based on relatively modest rates of methane increases from 2000 to 2006, but things changed dramatically afterwards, increasing 10-fold over the course of the next 10 years. The new figures factor an 8.4 percent increase in methane emissions from digestion (otherwise known as “enteric fermentation”) in dairy cows and other cattle, and a 36.7 percent increase in methane from manure, compared to previous IPCC-based estimates. The new report shows that methane accounted for approximately 16 percent of global greenhouse gas emissions in 2016. Other human activities, such as the production and transport of gas, oil and coal, along with the decay of our organic waste, also contribute to global methane emissions.

Importantly, the new estimates are 15 percent higher than global estimates produced by the US Environmental Protection Agency (EPA), and four percent higher than EDGAR (Emissions Database for Global Atmospheric Research).

“In many regions of the world, livestock numbers are changing, and breeding has resulted in larger animals with higher intakes of food,” noted Wolf in a release. “This, along with changes in livestock management, can lead to higher methane emissions.” To which she added: “Direct measurements of methane emissions are not available for all sources of methane. Thus, emissions are reported as estimates based on different methods and assumptions. In this study, we created new per-animal emissions factors—that is measures of the average amount of CH4 discharged by animals into the atmosphere—and new estimates of global livestock methane emissions.”

The new research shows that methane emissions slowed in the US, Canada, and Europe, but they’re rising elsewhere. Very likely, the rest of the world is catching up to first-world standards in terms of meat and dairy consumption.

“Among global regions, there was notable variability in trends in estimated emissions over recent decades,” said Ghassem Asrar, Director of JGCRI and a co-author of the new study. “For example, we found that total livestock methane emissions have increased the most in rapidly developing regions of Asia, Latin America, and Africa…We found the largest increases in annual emissions to be over the northern tropics, followed by the southern tropics.”

It’s not immediately clear how, or even if, these revised figures will impact livestock production or public policy, but at the individual level, it suggests we should cut back on our consumption of meat and dairy. The privilege we have over these animals, it would appear, now comes at a hefty price.

Update: An earlier version of this article included a statement suggesting that methane will exert a global warming potential 28 times greater than that of CO2 over then next 100 years. While methane has a unit for unit GWP that’s about 30 times that of CO2 on 100 year timescales, CO2 is still the dominant greenhosue gas in our atmosphere because there is so much more of it. The sentence in question has been removed.

Neil DeGrasse Tyson Says It Is ‘Too Late’ To Recover From Climate Change

Original Article

By Alexandra King

Scientist and astrophysicist Neil deGrasse Tyson said Sunday that, in the wake of devastating floods and damage caused by Hurricanes Harvey and Irma, climate change had become so severe that the country “might not be able to recover.”

In an interview on CNN’s “GPS,” Tyson got emotional when Fareed Zakaria asked what he made of Homeland Security Adviser Tom Bossert’s refusal to say whether climate change had been a factor in Hurricanes Harvey or Irma’s strength — despite scientific evidence pointing to the fact that it had made the storms more destructive.
“Fifty inches of rain in Houston!” Tyson exclaimed, adding, “This is a shot across our bow, a hurricane the width of Florida going up the center of Florida!”
“What will it take for people to recognize that a community of scientists are learning objective truths about the natural world and that you can benefit from knowing about it?” he said.
Tyson told Zakaria that he had no patience for those who, as he put it, “cherry pick” scientific studies according to their belief system.
“The press will sometimes find a single paper, and say, ‘Oh here’s a new truth, if this study holds it.’ But an emergent scientific truth, for it to become an objective truth, a truth that is true whether or not you believe in it, it requires more than one scientific paper,” he said.
“It requires a whole system of people’s research all leaning in the same direction, all pointing to the same consequences,” he added. “That’s what we have with climate change, as induced by human conduct.”
Tyson said he was gravely concerned that by engaging in debates over the existence of climate change, as opposed to discussions on how best to tackle it, the country was wasting valuable time and resources.
“The day two politicians are arguing about whether science is true, it means nothing gets done. Nothing,” he said. “It’s the beginning of the end of an informed democracy, as I’ve said many times. What I’d rather happen is you recognize what is scientifically truth, then you have your political debate.”
Tyson told Zakaria that he believed that the longer the delay when it comes to responding to the ongoing threat of climate change, the bleaker the outcome. And perhaps, he hazarded, it was already even too late.
“I worry that we might not be able to recover from this because all our greatest cities are on the oceans and water’s edges, historically for commerce and transportation,” he said.
“And as storms kick in, as water levels rise, they are the first to go,” he said. “And we don’t have a system — we don’t have a civilization with the capacity to pick up a city and move it inland 20 miles. That’s — this is happening faster than our ability to respond. That could have huge economic consequences.”