The Real Unknown of Climate Change: Our Behavior

The Real Unknown of Climate Change: Our Behavior

SOURCE: The New York Times

DATE: September 18, 2017

SNIP: In the 1970s, the experts made a best guess about how sensitive the Earth would be to greenhouse gases, and as evidence accumulates, that early estimate is holding up pretty well. Forecasts from the 1980s and 1990s about the rate of warming have proven fairly accurate, too, give or take 20 percent.

In fact, to the degree our scientists have made a systematic error, it has been to understate how quickly things would unravel.

The sea ice in the Arctic is collapsing in front of our eyes. Even more ominously, land ice is melting at an accelerating pace, threatening a future rise of the sea even faster than that of today.

Huge forest die-offs are beginning, even as the remaining forests work overtime to suck up some of the carbon pollution that humans are pumping out. We are already seeing heat waves surpassing 120 degrees Fahrenheit, sooner than many experts thought likely.

Every time some politician stands up and claims that climate science is rife with uncertainties, a more honest person would add that those uncertainties could just as easily go against us as in our favor.

The truth is that the single biggest uncertainty in climate science has nothing to do with the physics of the atmosphere, or the stability of the ice, or anything like that. The great uncertainty is, and has always been, how much carbon pollution humans are going to choose to pump into the air.

The Window Is Closing to Avoid Dangerous Global Warming

The Window Is Closing to Avoid Dangerous Global Warming

SOURCE: Scientific American and San Diego Tribune (video)

DATE: September 15, 2017

SNIP: Deadly climate change could threaten most of the world’s human population by the end of this century without efforts well beyond those captured in the Paris Agreement.

That’s the finding of a pair of related reports released yesterday by an international group of climate science and policy luminaries who warned that the window is closing to avert dangerous warming. They say carbon dioxide might have to be removed from the atmosphere.

Scientists Yangyang Xu and Veerabhadran Ramanathan found in a paper published in the Proceedings of the National Academy of Sciences (PNAS) that there already exists a 1 in 20 chance that the 2.2 trillion tons of carbon dioxide in the Earth’s atmosphere could cause an existential warming threat. This “fat tail” scenario would mean the world experiences “existential/unknown” warming by 2100 — defined in the report as more than 5 degrees Celsius above preindustrial levels.

The report also found a 50 percent chance that temperatures would rise to 4 C under a business-as-usual scenario, a less extreme but still highly dangerous level. The long-term goal of the Paris accord was to maintain warming well below 2 C.

Walruses on packed Alaska beach may have died in a stampede

Walruses on packed Alaska beach may have died in a stampede

SOURCE: CBC News

DATE: September 14, 2017

SNIP: Thousands of Pacific walrus are coming to Alaska’s northwest shore again in the absence of summer sea ice and not all are surviving.

A survey Monday of a mile of coastline near the Inupiaq Eskimo village of Point Lay found 64 dead walruses, the U.S. Fish and Wildlife Service told The Associated Press.

Most of the animals were younger than a year old. The cause of death is not known, said agency spokeswoman Andrea Medeiros, but stampedes — set off when startled walruses rush to the sea, crushing smaller animals — are a likely suspect.

Walrus dive hundreds of feet to eat clams on the ocean bottom, but unlike seals, they cannot swim indefinitely.

Historically, sea ice has provided a platform for rest and safety far from predators for mothers and calves north of the Bering Strait.

However, sea ice has receded much farther north in recent years because of global warming, beyond the shallow continental shelf, over water more than 3,050 metres deep. That’s far too deep for walruses to reach the ocean bottom.

Instead of staying on sea ice over the deep water, walruses have gathered on shore to rest.

The ultimate threat to walruses is the rapid loss of sea ice due to climate disruption, [Shaye Wolf, climate science director for the Center for Biological Diversity] said, adding that rollbacks of climate change protections by the Trump administration will further endanger the animals.

New Climate Risk Classification Created to Account for Potential “Existential” Threats

New Climate Risk Classification Created to Account for Potential “Existential” Threats

SOURCE: Scripps Institution of Oceanography and PNAS

DATE: September 14, 2017

SNIP: Researchers identify a one-in-20 chance of temperature increase causing catastrophic damage or worse by 2050.

A new study evaluating models of future climate scenarios has led to the creation of the new risk categories “catastrophic” and “unknown” to characterize the range of threats posed by rapid global warming. Researchers propose that unknown risks imply existential threats to the survival of humanity.

The risk assessment stems from the objective stated in the 2015 Paris Agreement regarding climate change that society keep average global temperatures “well below” a 2°C (3.6°F) increase from what they were before the Industrial Revolution.

Even if that objective is met, a global temperature increase of 1.5°C (2.7°F) is still categorized as “dangerous,” meaning it could create substantial damage to human and natural systems. A temperature increase greater than 3°C (5.4°F) could lead to what the researchers term “catastrophic” effects, and an increase greater than 5°C (9°F) could lead to “unknown” consequences which they describe as beyond catastrophic including potentially existential threats.

Nearly 2 million acres of land are burning across the US in one of the worst fire seasons we’ve ever seen

Nearly 2 million acres of land are burning across the US in one of the worst fire seasons we’ve ever seen

SOURCE: Business Insider and San Francisco Chronicle

DATE: September 14, 2017

SNIP: Almost 2 million acres of land — an area nearly the size of Rhode Island and Delaware combined — are currently aflame, according to the September 14 daily report by the National Interagency Fire Center. There are more than 100 active wildfires and at least 41 uncontained large blazes, battled by more than 25,000 responders, the National Guard, and half a battalion of active-duty soldiers.

A staggering amount of land has burned so far this season — more than 8 million acres, along with more than 500 homes and other structures, according to the Fish and Wildlife Service (FWS). The Forest Service has spent more than $1.75 billion fighting fires so far this fiscal year, and the Interior Department has spent more than $391 million, the Los Angeles Times reported.

Research indicates that human-caused climate change has already had a significant increase on the overall number and size of fires. The amount of land burned in the US since 1984 was double what would have been expected without the effects of climate change in that period. And wildfire season has become about two and a half months longer since 1970 (a trend that’s expected to continue).

Red list: ash trees and antelopes on the brink of extinction

Red list: ash trees and antelopes on the brink of extinction

SOURCE: The Guardian

DATE: September 14, 2017

SNIP: Native ash trees, abundant across North America, are on the brink of extinction as an invasive beetle ravages forests, according to the new red list of threatened species from the International Union for Conservation of Nature (IUCN).

The list now includes more than 25,000 species at risk of extinction and the scientists warn that species, such as the American ashes and five African antelopes, that were thought to be safe, are now disappearing faster than they can be counted.

The six most common ash tree species in North America, representing nine billion trees, have entered the red list for the first time, with five assessed as being in the most at-risk category of critically endangered. They are being destroyed by the fast-spreading emerald ash borer beetle, which arrived in Michigan from Asia in the late 1990s in infested shipping pallets.

The beetle has already killed tens of millions of trees and can wipe out a whole forest in six years. Climate change is also helping the alien invader enter new areas that were previously too cold.

Stunning new analysis reveals just how unprecedented Harvey was

Stunning new analysis reveals just how unprecedented Harvey was

SOURCE: Think Progress

DATE: September 14, 2017

SNIP: Hurricane Harvey’s landfall in Texas was “unprecedented” and “beyond anything experienced,” as the National Weather Service described it late last month. Now scientists are beginning to quantify just how unprecedented it was.

A study released Friday by Metstat, a weather-analysis company specializing in “detailed precipitation analysis” and “weather frequency analysis,” found that Harvey delivered a stunning once-in-25,000-year deluge over much of southeast Texas.

Some places saw an unimaginable once-in-500,000-year deluge, which translates to a 0.0002 percent chance of this deluge occurring in any given year.

Since global warming has been making extreme precipitation events more likely, however, the U.S. won’t have to wait 25,000 years to witness the next event of Harvey’s proportion.

As climatologist Michael Mann explained during the storm, “the kind of stalled weather pattern that is drenching Houston is precisely the sort of pattern we expect because of climate change.” Climate science predicted a weaker jet stream, and Harvey stalled because of a weakened jet stream.

The great nutrient collapse

The great nutrient collapse

SOURCE: Politico

DATE: September 13, 2017

SNIP: These experiments and others like them have shown scientists that plants change in important ways when they’re grown at elevated CO2 levels. Within the category of plants known as “C3″―which includes approximately 95 percent of plant species on earth, including ones we eat like wheat, rice, barley and potatoes―elevated CO2 has been shown to drive down important minerals like calcium, potassium, zinc and iron. The data we have, which look at how plants would respond to the kind of CO2 concentrations we may see in our lifetimes, show these important minerals drop by 8 percent, on average. The same conditions have been shown to drive down the protein content of C3 crops, in some cases significantly, with wheat and rice dropping 6 percent and 8 percent, respectively.

Earlier this summer, a group of researchers published the first studies attempting to estimate what these shifts could mean for the global population. Plants are a crucial source of protein for people in the developing world, and by 2050, they estimate, 150 million people could be put at risk of protein deficiency, particularly in countries like India and Bangladesh. Researchers found a loss of zinc, which is particularly essential for maternal and infant health, could put 138 million people at risk. They also estimated that more than 1 billion mothers and 354 million children live in countries where dietary iron is projected to drop significantly, which could exacerbate the already widespread public health problem of anemia.

Taking the Long View: The ‘Forever Legacy’ of Climate Change

Taking the Long View: The ‘Forever Legacy’ of Climate Change

SOURCE: Yale Environment 360

DATE: September 12, 2017

SNIP: Although we will unquestionably have a less hospitable climate in 2100 than today, that will be nothing compared to what might lie in store in 2200 and beyond. Yes, in 2100, sea levels might be three or more feet higher than today, which will be bad for low-lying nations like Bangladesh and U.S. states like Florida. But if greenhouse gas emissions continue at roughly today’s levels for another century, that may mean that sea levels 500 years from now would be nearly 50 feet higher as the Greenland and Antarctic ice sheets melt. That would mean losing large swaths of coastal areas worldwide. This is not alarmism; this is where the science takes us.

Desert locusts: new risks in the light of climate change

Desert locusts: new risks in the light of climate change

SOURCE: Cirad

DATE: September 9, 2017

SNIP: The desert locust is an invasive species that is both well known and feared because of the large-scale agricultural damage it can cause. It is particularly closely monitored, to prevent the risks of outbreaks and invasions. Climate change could modify its distribution area, meaning a new threat to agriculture, according to a study published in the journal Global Change Biology by researchers from CIRAD and INRA.