Category Archives: Science

Map of the day: Antarctic sea ice hits a new low


We begin with two images from the National Snow and Ice Data Center.

First, the extent of Antarctic sea ice as of 20 February 2017, with the yellow line indicating the average sea ice coverage in recent years:

blog-ice-map

Second, a graph showing the progression of coverage in the 2016-2017 cycle [blue line] compared to other years:

blog-ice-chartWhat make this summer’s record low even more remarkable is that it immediately follows years of record highs. And we say summer because that’s the current season in the Southern Hemisphere.

More from MercoPress:

This year the extent of summer sea ice in the Antarctic is the lowest on record. The Antarctic sea ice minimum marks the day – typically towards end of February – when sea ice reaches its smallest extent at the end of the summer melt season, before expanding again as the winter sets in. This year, sea ice extent contracted to 2.28m sq km on 13 February, according to data from the US National Snow and Ice Data Center (NSIDC).

The extent is a fraction smaller than a previous low of 884,173 sq miles recorded on 27 February 1997 in satellite records dating back to 1979. Scientists, including those at British Antarctic Survey, are monitoring the data closely and trying to understand why this year is presenting a minimum.

BAS climate scientist Dr James Pope says: “At this time, so close to minimum event, it is difficult to identify what is causing the record minimum and whether anything significant has changed. Sea ice is highly variable on year-to-year time-scales and therefore the recent record maximum extent from a couple of years ago and this year’s record minimum could both be the result of short- term changes rather than longer-term trends.

“What’s interesting is that Antarctic sea ice has been steadily increasing in size, year on year from the 1970s. So what’s happening now is against the trend. And whilst it’s significant, we won’t know for a couple of years whether this is a single event or a switch away from the previously observed increase. We will now study the data with interest and look at what is causing this minimum.”

Record El Niño devastates Pacific Coast beaches


Following up on the previous post, a look at another aspect of climate change.

Record waves generated by El Niño have devastated beaches all along the Pacific coast, and as a new study [open access] concludes, “climate change projections suggest a possible increase in the frequency of extreme El Niño and La Niña events,” meaning this year’s disaster could be just the beginning of worse to come.

More from the U.S. Geological Survey:

In a new study, U.S. Geological Survey scientists and their colleagues document how the 2015-16 winter featured one of the most powerful El Niño climate events of the last 145 years.

Investigating 29 beaches along the U.S West Coast from Washington to southern California, researchers found that winter beach erosion was 76 percent above normal, by far the highest ever recorded, and most beaches in California eroded beyond historical extremes. If severe El Niño events such as this one become more common in the future as studies suggest, this coastal region, home to more than 25 million people, will become increasingly vulnerable to coastal hazards, independently of projected sea level rise.

The authors assessed seasonal changes on 29 beaches along approximately 2000 kilometers (1243 miles) of the U.S. West Coast. Surveying the beaches included making 3-D surface maps and cross-shore profiles using aerial lidar (light detection and ranging), GPS topographic surveys, and direct measurements of sand levels, combined with wave and water level data at each beach, collectively spanning 1997-2016. Winter beach erosion or the removal and loss of sand from the beach is a normal seasonal process, but the extent of erosion can be more severe during El Niño events than in other years.

“Wave conditions and coastal response were unprecedented for many locations during the winter of 2015-16. The winter wave energy equaled or exceeded measured historical maximums along the U.S. West Coast, corresponding to extreme beach erosion across the region,” said USGS geologist and lead author of the report, Patrick Barnard.

The 2015-16 El Niño was one of the three strongest events ever recorded, along with El Niño winters of 1982-83 and 1997-98. While most beaches in California eroded beyond historical extremes, some beaches fared better. “The condition of the beach before the winter of 2015 strongly influenced the severity of erosion and the ability of the beach to recover afterward through natural replenishment processes,” said UC Santa Barbara marine ecologist and co-author David Hubbard.

Rivers still supply the primary source of sand to California beaches, despite long-term reductions in the 20th century due to extensive dam construction. But as California is in the midst of a major drought, the resulting lower river flows equated to even less sand being carried to the coast to help sustain beaches.

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Scientists find a number for human climate change


From “The Anthropocene equation” [open access], a scientific review of climate change states, a look at the rates of change in earth systems and the degree to which human activity has accelerated them. Click on the image to enlarge.

From “The Anthropocene equation” [open access], a scientific review of climate change states, a look at the rates of change in earth systems and the degree to which human activity has accelerated them. Click on the image to enlarge.

And it’s a frightening number, too.

From the Australian National University:

Humans are causing the climate to change 170 times faster than natural forces, new research co-led by The Australian National University (ANU) has found.

Co-researcher Professor Will Steffen from ANU said the study for the first time came up with a mathematical equation to describe the impact of human activity on the Earth system, known as the Anthropocene equation.

“Over the past 7,000 years the primary forces driving change have been astronomical – changes in solar intensity and subtle changes in orbital parameters, along with a few volcanoes. They have driven a rate of change of 0.01 degrees Celsius per century,” said Professor Steffen, from the Fenner School of Environment and Society and the Climate Change Institute at ANU.

“Human-caused greenhouse gas emissions over the past 45 years have increased the rate of temperature rise to 1.7 degrees Celsius per century, dwarfing the natural background rate.”

The paper published in The Anthropocene Review examines the Earth system as a single complex system and assesses the impact of human activities on the system’s trajectory.

“We are not saying the astronomical forces of our solar system or geological processes have disappeared, but in terms of their impact in such a short period of time they are now negligible compared with our own influence,” Professor Steffen said.

“Crystallising this evidence in the form of a simple equation gives the current situation a clarity that the wealth of data often dilutes.

“It also places the contemporary human impact in the context of the great forces of nature that have driven Earth system dynamics over billions of years.”

Professor Steffen said humanity still had a chance to prevent catastrophic climate change, but time was rapidly running out.

“The global economy can function equally well with zero emissions. Research shows we can feed nine billion people – the projected world population by 2050 – and reduce greenhouse gas emissions at the same time,” he said.

Are Monarch butterflies headed for extinction?


Monarch butterflies have always been a personal favorite, those remarkable orange-winged critters whose presence always brightens a day.

As we wrote last year:

When we first arrived in California in 1967, one of the first mysteries we encountered was attached to a Monarch butterfly, one of those magnificently garbed creatures we had first found so fascinating as a child years earlier.

The mystery was a small paper wheel imprinted with a serial number and a phone number we were to call if we chanced upon the little critter.

Aha! A story! we thought — and we were right.

The phone number connected us to a Canadian university, where entomologists were studying the migrational patterns of creature that managed to navigate its way from the plains of our neighbor to the north to a forest in the heartland of our neighbor to the south — a remarkably odyssey worthy of a Greek bard.

But now, we learn, those delightful creatures may soon vanish from the earth.

From The Ecologist:

It’s been another disastrous year for North America’s Monarch butterflies, with the insect’s population down 27% in a single year. The sudden decline is blamed on severe winter storms in Mexico, and the impacts of GMO crops, herbicides and insecticides on US farms.

The annual overwintering count of monarch butterflies confirms. . .that this year’s population is down by 27% from last year’s count, and down by more than 80% from the mid-1990s. This dramatic decline indicates that America’s most well-known butterfly is at ongoing risk of extinction.

This year’s drastic decline is attributed in part to extreme winter storms that killed millions of monarchs last March in Mexico’s mountain forests where 99% of the world’s monarchs migrate for the winter.

“The monarch butterfly is still in really big trouble and still needs really big help if we are going to save this beloved orange and black wonder for future generations”, said Tierra Curry, a senior scientist at the Center for Biological Diversity.

A recent study by the US Geological Survey concluded that there is a substantial probability that monarch butterflies east of the Rockies could decline to such low levels that they face extinction. Researchers estimate the probability that the monarch migration could collapse within the next 20 years is between 11% and 57%.

And if you think the Endangered SPecies Act will help save this or any onther critter, think again.

There’s now a major move afoot by Congressional Republicans to either gut the law or abolish it altogether.

Likely Trump science pick a climate change skeptic


And he calls colleagues who believe in it “glassy eyed cultists.

Oh, and he also favors censoring federal scientists.

From the Guardian:

The man tipped as frontrunner for the role of science adviser to Donald Trump has described climate scientists as “a glassy-eyed cult” in the throes of a form of collective madness.

William Happer, an eminent physicist at Princeton University, met Trump last month to discuss the post and says that if he were offered the job he would take it. Happer is highly regarded in the academic community, but many would view his appointment as a further blow to the prospects of concerted international action on climate change.

“There’s a whole area of climate so-called science that is really more like a cult,” Happer told the Guardian. “It’s like Hare Krishna or something like that. They’re glassy-eyed and they chant. It will potentially harm the image of all science.”

Trump has previously described global warming as “very expensive … bullshit” and has signalled a continued hardline stance since taking power.

>snip<

Happer also supports a controversial crackdown on the freedom of federal agency scientists to speak out about their findings, arguing that mixed messages on issues such as whether butter or margarine is healthier, have led to people disregarding all public health information.

Map of the day: Record heat wave Down Under


From NASA’s Earth Observer:

blog-australia

And now for their report, remarkable for avoid any mention of words climate change, clear evidence of the chill felt throughout the ranks of the scientists who draw their paychecks from Uncle Sam:

Heat waves are not unusual in Australia. A subtropical belt of high pressure that flows over the continent regularly delivers pulses of hot, dry air to the surface in the summer. Yet even by Australian standards, the intense heat wave of February 2017 has been remarkable.

When a high-pressure system stalled over central Australia, extreme temperatures emerged first in South Australia and Victoria and then spread to New South Wales, Queensland, and Northern Territory. With overheated bats dropping from trees and bushfires burning out of control, temperatures smashed records in many areas.

This map shows peak land surface temperatures between February 7 and 14, 2017, a period when some of the most extreme heating occurred. The map is based on data collected by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite. Note that it depicts land surface temperatures, not air temperatures. Land surface temperatures reflect how hot the surface of the Earth would feel to the touch in a particular location. They can sometimes be significantly hotter or cooler than air temperatures. (To learn more about LSTs and air temperatures, read: Where is the Hottest Place on Earth?)

On February 12, 2017, air temperatures rose to 46.6°C (115.9°F) in the coastal city of Port Macquarie, New South Wales, breaking the city’s all-time record by 3.3 degrees Celsius (5.9 degrees Fahrenheit). Two days earlier, the average maximum temperature across all of New South Wales hit a record-setting 42.4°C (108.3°F)—a record that was broken the next day when it rose to 44.0°C (111.2°F).

In some places, the duration of the heatwave has been noteworthy. Mungindi, a town on the border of Queensland and New South Wales, endured 52 days in a row when maximum temperatures exceeded 35°C (95°F)—a record for New South Wales.

Many scientists see exceptional heat waves like this as part of a broader trend. For instance, one study published by the Climate Council of Australia concluded that heatwaves—defined as at least three days of unusually high temperatures—grew significantly longer, more intense, and frequent between 1971 and 2008.

A plastic that makes you fat, starting in the womb


And it does it by interfering with the body’s signalling system that tells you when you’ve eaten enough.

We posted reams about studies of bisphenols, the chemicals widely present in food packaging, including cans and bottles, and linked to a wide rabnge of disorders including breast cancer, endometriosis, ADHD, asthma, behaviorial problems in girls, birth defects, prostate cancer and lowered sperm counts, and more.

And now a new study reveals that the chemical might play a crucial role in America’s growing [literally] obesity epidemic.

From the Endocrine Society:

An expectant mother’s exposure to the endocrine-disrupting chemical bisphenol A (BPA) can raise her offspring’s risk of obesity by reducing sensitivity to a hormone responsible for controlling appetite, according to a mouse study published in the Endocrine Society’s journal Endocrinology.

BPA is a chemical found in a variety of food containers, including polycarbonate plastic water bottles and can linings. BPA can interfere with the endocrine system by mimicking estrogen, one of the main sex hormones found in women. Research indicates BPA exposure is nearly universal. More than 90 percent of people tested in population studies had detectable levels of BPA and compounds produced when it is metabolized by the body in their urine.

As of 2014, nearly 100 epidemiological studies had been published tying BPA to various health problems, according to the Society and IPEN’s Introduction to Endocrine-Disrupting Chemicals.

The new study found mice born to mothers exposed to BPA were less responsive to the hormone leptin, which is sometimes called the satiety hormone. Leptin helps inhibit the appetite by reducing hunger pangs when the body does not need energy. The hormone sends signals to the hypothalamus region of the brain to suppress the appetite.

“Our findings show that bisphenol A can promote obesity in mice by altering the hypothalamic circuits in the brain that regulate feeding behavior and energy balance,” said the study’s senior author, Alfonso Abizaid, Ph.D., of the Department of Neuroscience at Carleton University in Ottawa, Canada. “Low level prenatal exposure to BPA delays a surge of leptin after birth that allows mice to develop the proper response to the hormone. BPA exposure permanently alters the neurobiology in the affected mice, making them prone to obesity as adults.”

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