Sunday, July 11, 2021

Earth’s cryosphere shrinking by 87,000 square kilometers per year

The second word below is a lie. The small shrinkage in ice cover is NOT global. The ice-cover actually INCREASED overall in the Southern hemisphere. See the original paper. So you can calculate a global average but there is no corresponding global process

The global cryosphere—all of the areas with frozen water on Earth—shrank by about 87,000 square kilometers (about 33,000 square miles), a area about the size of Lake Superior, per year on average, between 1979 and 2016 as a result of climate change, according to a new study. This research is the first to make a global estimate of the surface area of the Earth covered by sea ice, snow cover and frozen ground.

The extent of land covered by frozen water is just as important as its mass because the bright white surface reflects sunlight so effectively, cooling the planet. Changes in the size or location of ice and snow can alter air temperatures, change the sea level and even affect ocean currents worldwide.

The new study is published in Earth’s Future, AGU’s journal for interdisciplinary research on the past, present and future of our planet and its inhabitants.

“The cryosphere is one of the most sensitive climate indicators and the first one to demonstrate a changing world,” said first author Xiaoqing Peng, a physical geographer at Lanzhou University. “Its change in size represents a major global change, rather than a regional or local issue.”

The cryosphere holds almost three-quarters of Earth’s fresh water, and in some mountainous regions, dwindling glaciers threaten drinking water supplies. Many scientists have documented shrinking ice sheets, dwindling snow cover and loss of Arctic sea ice individually due to climate change. But no previous study has considered the entire extent of the cryosphere over Earth’s surface and its response to warming temperatures.

Peng and his co-authors from Lanzhou University calculated the daily extent of the cryosphere and averaged those values to come up with yearly estimates. While the extent of the cryosphere grows and shrinks with the seasons, they found that the average area covered by Earth’s cryosphere has contracted overall since 1979, correlating with rising air temperatures.

The shrinkage primarily occurred in the Northern Hemisphere, with a loss of about 102,000 square kilometers (about 39,300 square miles), or about half the size of Kansas, each year. Those losses are offset slightly by growth in the Southern Hemisphere, where the cryosphere expanded by about 14,000 square kilometers (5,400 square miles) annually. This growth mainly occurred in the sea ice in the Ross Sea around Antarctica, likely due to patterns of wind and ocean currents and the addition of cold meltwater from Antarctic ice sheets.

The estimates showed that not only was the global cryosphere shrinking but that many regions remained frozen for less time. The average first day of freezing now occurs about 3.6 days later than in 1979, and the ice thaws about 5.7 days earlier.

“This kind of analysis is a nice idea for a global index or indicator of climate change,” said Shawn Marshall, a glaciologist at the University of Calgary, who was not involved in the study. He thinks that a natural next step would be to use these data to examine when ice and snow cover give Earth its peak brightness, to see how changes in albedo impact the climate on a seasonal or monthly basis and how this is changing over time.

To compile their global estimate of the extent of the cryosphere, the authors divided up the planet’s surface into a grid system. They used existing data sets of global sea ice extent, snow cover and frozen soil to classify each cell in the grid as part of the cryosphere if it contained at least one of the three components. Then they estimated the extent of the cryosphere on a daily, monthly and yearly basis and examined how it changed over the 37 years of their study.

The authors say that the global dataset can now be used to further probe the impact of climate change on the cryosphere, and how these changes impact ecosystems, carbon exchange and the timing of plant and animal life cycles.

Paper title: “A Holistic Assessment of 1979–2016 Global Cryospheric Extent”


Climate change could make us SMALLER: Rising temperatures drive the evolution of smaller human bodies – and brains, study warns

That's why dinosaurs were so small, I guess

Climate has changed the size of human bodies and, to some extent, human brains, research suggests.

The average body size has fluctuated over the last million years and is strongly linked to temperature, according to the new study.

Colder, harsher climates drove the evolution of larger body sizes, while warmer climates led to smaller bodies.

And while brain size has also changed dramatically, it did not evolve in tandem with body size, researchers found.

The study, led by the Universities of Cambridge and Tubingen, gathered measurements of body and brain size for more than 300 fossils from the genus Homo found across the globe.

Experts pinpointed the specific climate experienced by each fossil when it was a living human by combining this data with a reconstruction of the world's regional climates over the last million years.

The study, led by the Universities of Cambridge and Tubingen, gathered measurements of body and brain size for more than 300 fossils from the genus Homo found across the globe +2
The study, led by the Universities of Cambridge and Tubingen, gathered measurements of body and brain size for more than 300 fossils from the genus Homo found across the globe

Our brains could shrink even more - thanks to our reliance on technology
Brain size in our species appears to have been shrinking since the beginning of the Holocene (around 11,650 years ago).

The increasing dependence on technology, such as an outsourcing of complex tasks to computers, may cause brains to shrink even more over the next few thousand years, researchers suggest.

Our species, Homo sapiens, emerged around 300,000 years ago in Africa.

But the genus Homo has existed for much longer, and includes the Neanderthals and other extinct, related species such as Homo habilis and Homo erectus.

A defining trait of the evolution of our genus is a trend of increasing body and brain size.

Compared to earlier species such as Homo habilis, humans are 50 per cent heavier and our brains are three times larger.

Professor Andrea Manica, a researcher in the University of Cambridge's department of zoology, who led the study, said: 'Our study indicates that climate – particularly temperature – has been the main driver of changes in body size for the past million years.'

He added: 'We can see from people living today that those in warmer climates tend to be smaller, and those living in colder climates tend to be bigger.

'We now know that the same climatic influences have been at work for the last million years.'

The researchers also found that brain size tended to be larger when Homo was living in habitats with less vegetation, like open steppes and grasslands, but also in ecologically more stable areas.

In combination with archaeological data, the results suggest those living in these habitats hunted large animals as food – a complex task that might have driven the evolution of larger brains.

Dr Manuel Will at the University of Tubingen, Germany, first author of the study, said: 'We found that different factors determine brain size and body size – they're not under the same evolutionary pressures.

'The environment has a much greater influence on our body size than our brain size.'

He added: 'There is an indirect environmental influence on brain size in more stable and open areas: the amount of nutrients gained from the environment had to be sufficient to allow for the maintenance and growth of our large and particularly energy-demanding brains.'

The research also indicates that non-environmental factors were more important for driving larger brains than climate, prime candidates being the added cognitive challenges of increasingly complex social lives, more diverse diets, and more sophisticated technology.

Researchers say the human physique is still adapting to different temperatures, with on average larger-bodied people living in colder climates today.

Brain size in our species appears to have been shrinking since the beginning of the Holocene (around 11,650 years ago).

The increasing dependence on technology, such as an outsourcing of complex tasks to computers, may cause brains to shrink even more over the next few thousand years, researchers suggest.

The research, published in Nature Communications, was funded by the European Research Council and the Antarctic Science Platform.


Story on Pending Coffee Collapse Is Long on Alarm but Short on Facts (Again)

An article in Fort Wayne Journal Gazette (credited to the Washington Post as the original source) highlighted by Google News today in a search for the term “climate change,” claims global warming is threatening a coffee crisis. This is false. Across its range, coffee production and yields per acre have been setting records with regularity during the recent period of modest warming.

The author of the article, titled “Climate change puts coffee at risk,” says the world’s coffee growers fear coffee production will suffer due to climate change, unless new varieties of coffee beans are developed.

“Climate change could spell disaster for coffee, a crop that requires specific temperatures to flourish and that is highly sensitive to a range of pests. So scientists are racing to develop more tenacious strains of one of the world’s most beloved beverages....

‘Coffee is not ready to adapt to climate change without help,’ said Doug Welsh, the vice president and roastmaster of Peet’s Coffee, which has invested in WCR’s research.”

Computer model projections of future temperatures are being used to gin up fear that coffee crops are threatened by modestly warmer temperatures. Yet, computer models are notorious for badly overstating actual temperatures [See Figure]1, and real world data show the earth’s modest warming has accompanied record coffee production and yields.

Coffee producers as a whole are not struggling. The U.N.’s Food and Agriculture Organization reports coffee production and yields nearly doubled between 1993 and 2019. Global coffee production increased from approximately 5.6 million tons in 1993 to more than 10.3 million tons in 2019. Indeed, FAO data show globally coffee set new records for both production and yield 12 times since 1993. The most recent records for production and yield were set in 2018.

What’s true for the world as a whole is also true of the world’s top coffee producing countries. Brazil, Vietnam, Columbia, Indonesia, and Ethiopia (listed in order of production), have each experienced substantial growth in coffee production during the recent period of modest warming.

According to data from the Food and Agriculture Organization of the United Nations, from 1993 to 2019:

Coffee production in Brazil grew by more than 135 percent;

Coffee production in Vietnam increased by more than 1,137 percent;

Coffee production in Columbia increased by more than 8 percent;

Coffee production in Indonesia grew by more than 73 percent; and
Coffee production in Ethiopia expanded by more than 168 percent.

The International Coffee Organization reports coffee producers face problems not from difficulty growing crops, but because crop conditions and crop production is so strong that supply is outpacing demand. Rapid growth in coffee crop yields are driving down coffee prices. In 2018/2019 coffee production grew by 3.7 percent overall, with Arabica bean production increasing by 1.8 percent and Robusta beans growing 6.7 percent. This marked the second consecutive year of declining prices amidst growing surpluses.

In the few areas within countries where farmers have ceased growing coffee and production has declined, the evidence indicates the reason is not poor climate conditions but rather increased international competition and low prices.

Sorry, to disabuse people of your climate alarm fairy tale, Fort Wayne Journal Gazette and Washington Post, but there is no climate/coffee crisis. Coffee production keeps growing as the Earth modestly warms.


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