Global Warming

Climate imperils Ethiopia’s coffee

Climate change could wipe out more than half of Ethiopia’s coffee production unless farmers move to higher ground, scientists warned Monday.

Climbing temperatures and dwindling rainfall have already degraded prime growing areas, such as the Zege Peninsula, they reported in the journal Nature Plants.

If global warming continues unabated, up to 60 percent of land currently used to grow coffee beans will be unsuitable for production by the last three decades of the century.

Home of the prized Coffea arabica plant, Ethiopia is the world’s fifth biggest producer of beans, after Brazil, Vietnam, Colombia and Indonesia, according to the International Coffee Organization.

Over the last 50 years, however, average temperatures across the country have risen by about 1.5 degrees Celsius (2.7 degrees Fahrenheit), and rainfall in key regions has become spotty. Coffee areas that once flourished are in decline.

Global Warming

Wetter Tropics

NASA says Earth’s tropical climates are likely to experience more rainfall than predicted as the planet continues to warm, even as the region’s high clouds thin out in the decades ahead.

In a counterintuitive process of heating and cooling, less high cloudiness means the air above the tropical surface would actually cool without those clouds capping in the heat below.

Researchers say this would alter Earth’s “energy budget” and create more tropical rainfall. Most climate models have failed to factor in this process, thus underestimating future tropical rainfall.

Global Warming

Climate Change Pushing Tropical Diseases Toward Arctic

Temperature changes around the globe are pushing human pathogens of all kinds into unexpected new areas, raising many new risks for people.

Among the most well-documented of these new threats is the spread of ocean-traveling Vibrio bacteria that can sicken or kill unsuspecting swimmers or shellfish eaters, even though these bacteria need warm water to survive.

Before 2004, for example, Alaskan waters were thought to be too cold to support enough Vibrio to cause disease. But around July 4 that year, aboard a small cruise ship, several dozen passengers got sick after eating oysters from the Gulf of Alaska—more than 1,000 kilometers further north than the previous northernmost Vibrio incident. The waters that summer around the oyster beds were 2 degrees warmer than they’d ever been.

Already in Europe, for example, the ticks that carry Lyme disease, once largely limited to the south, are finding new hosts as far north as Sweden. Some winters aren’t cold enough to kill the young nymphs, which also allows them to stick around another season. A similar issue has struck a region near Russia’s Ural Mountains, which has seen a 23-fold increase in tick-borne encephalitis in 20 years. Temperature changes have lengthened the tick season by half (the same problem is hammering moose). Meanwhile, the sandflies that host parasites that cause leishmaniasis, some varieties of which cause skin lesions or spleen and liver damage, are showing up in north Texas.

Evidence suggests, for example, that moisture changes could alter the spread of the soil-borne fungi that give rise to the American Southwest’s flu-like valley fever. Infections that aerosolize, like tuberculosis, can linger longer and perhaps be transported easier in regions of the world projected to become more humid. New research suggests the spread of blood-sucking kissing bugs that contain parasites that carry Chagas Disease may well help that affliction spread into North America. Already millions of people worldwide, mostly in South America, suffer from chronic Chagas, which can lead to life-threatening heart damage and stroke.

Global Warming

Climate change is shrinking the Colorado River

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Lake Powell, photographed April 12, 2017. The white ‘bathtub ring’ at the cliff base indicates how much higher the lake reached at its peak, nearly 100 feet above the current level.

The nation’s two largest reservoirs, Lake Mead on the Arizona/Nevada border and Lake Powell on the Arizona/Utah border, were brim full in the year 2000. Four short years later, they had lost enough water to supply California its legally apportioned share of Colorado River water for more than five years. Now, 17 years later, they still have not recovered.

This ongoing, unprecedented event threatens water supplies to Los Angeles, San Diego, Phoenix, Tucson, Denver, Salt Lake City, Albuquerque and some of the most productive agricultural lands anywhere in the world. It is critical to understand what is causing it so water managers can make realistic water use and conservation plans.

While overuse has played a part, a significant portion of the reservoir decline is due to an ongoing drought, which started in 2000 and has led to substantial reductions in river flows. Most droughts are caused by a lack of precipitation. However, research shows that about one-third of the flow decline was likely due to higher temperatures in the Colorado River’s Upper Basin, which result from climate change.

This distinction matters because climate change is causing long-term warming that will continue for centuries.

In the study, researchers found the period from 2000 to 2014 is the worst 15-year drought since 1906, when official flow measurements began. During these years, annual flows in the Colorado River averaged 19 percent below the 20th-century average.

During a similar 15-year drought in the 1950s, annual flows declined by 18 percent. But during that drought, the region was drier: rainfall decreased by about 6 percent, compared to 4.5 percent between 2000 and 2014. Why, then, is the recent drought the most severe on record?

The answer is simple: higher temperatures. From 2000 to 2014, temperatures in the Upper Basin, where most of the runoff that feeds the Colorado River is produced, were 1.6 degrees Fahrenheit higher than the 20th-century average. This is why we call this event a hot drought. High temperatures continued in 2015 and 2016, as did less-than-average flows. Runoff in 2017 is expected to be above average, but this will only modestly improve reservoir volumes.

High temperatures affect river levels in many ways. Coupled with earlier snow melt, they lead to a longer growing season, which means more days of water demand from plants. Higher temperatures also increase daily plant water use and evaporation from water bodies and soils. In sum, as it warms, the atmosphere draws more water, up to 4 percent more per degree Fahrenheit from all available sources, so less water flows into the river. These findings also apply to all semi-arid rivers in the American Southwest, especially the Rio Grande.

Global Warming

Undoing Trump

San Francisco Mayor Ed Lee became the 13 U.S. mayor to use public resources to repost Environmental Protection Agency (EPA) web pages on global warming that were deleted by the Trump administration earlier this year.

Lee said the “American people are entitled to the publicly-funded EPA research on climate change” in announcing his office would post the deleted pages on the city’s Open Gov website.

Drinking Water Along The US-Mexico Border Threatened By Global Warming

Global warming looms large in the Southwest as rising temperatures threaten to diminish already scarce water supplies. A 2014 United Nations report suggests that globally, the burden of climate change will impact the poor the most. Some of the most marginalized communities in the United States are found along the U.S.-Mexico border.

Some people living along the border already live without access to running water. In New Mexico, 90 percent of the population gets their drinking water from the ground — fed by melting snow packs from mountains, rivers and streams. But with rising temperatures and warmer and shorter snow seasons, less of that water is making it into the aquifer.

To keep up with plummeting water levels, municipal and private wells are being drilled deeper into the earth. But for people living in low-income communities along the border known as colonias, that is not a viable option.

Many residents depend on shallow wells dug by hand. Water is struck 25 feet below peoples’ homes, the families cannot not drink it because it is not safe. Instead, they used it to shower and do their laundry, until they realized that was a problem too. The clothes was like turning yellow and rotten.

A 2015 NASA climate study projects Southwest water supplies will only be diminished further with an even harsher drought projected in the next 30 years.

Florida reef rescuers race to keep pace with climate change

Ten years ago, when scientists in South Florida began a massive rescue effort to rebuild the nation’s only inshore reef, replanting nursery-grown staghorn coral with a gardening technique perfected in the Pacific seemed like an easy solution.

From Key West to Fort Lauderdale, volunteers and scientists planted thousands of staghorns in reef rescues. More than 90 percent of Lirman’s corals survived — about 10 percent more than expected —signaling a rousing success. The work helped shift reef restoration from uglier, more costly engineered artificial reefs created with scuttled ships, which are also more susceptible to invasive species and vulnerable to sea rise. Labs expanded to meet the growing demand, added more kinds and perfected techniques.

Then came back-to-back bleaching events that started in 2014. In 2015, more than half of Lirman’s transplanted staghorns died. Suddenly, the reef gardeners were faced with a daunting new obstacle: climate change.

So he began intentionally stressing the coral — exposing them to heat and light — in his lab. Those that recover are more hardened to future stresses.

If his field trial works, Baker said it’s possible to replicate the hardening elsewhere in the world, like the Great Barrier reef, where an ongoing bleaching has ravaged an area larger than Italy and covering two-thirds of the reef.

Global Warming

Drowning Communities

Isle de Jean Charles, a small island in southeastern Louisiana’s bayous, is drowning as the Gulf of Mexico rises. Twenty-nine homes remain, housing 100 people, but they are all being relocated because the flooding is unstoppable. The island has already lost 98% of its land since 1955, making it one of the most visible victims of climate change — so far. The residents can either leave their homes or die in them, and they are leaving.

Climate change is affecting larger coastal areas in the U.S., from Alaska down to Florida and Louisiana. Climate-induced migration is now a concrete reality for US citizens, not an abstract idea for politicians to talk about.

Global Warming

Frost Season

A US researcher says the frost-free season across North America is now 10 days longer than it was a century ago, mainly because of altered atmospheric circulation patterns and, to a lesser extent, global warming.

“If you ask a U.S. forecaster what determines the first fall frost, they’ll say a cold air mass coming down out of Canada, clearly due to circulation,” said University of Utah atmospheric scientist Court Strong. “There’s a role for warming, but on the other hand, forecasters will tell you there’s clearly a role for circulation as well.”

Of the 10 additional days that North America is now frost-free, Strong says only three can be directly attributed to a warmer climate. But other scientists have said that global warming has actually altered atmospheric circulation patterns.

Global Warming

Hawaii Rebuffs Trump by Enacting Laws Supporting Paris Agreement

Following President Donald Trump’s announcement withdrawing the United States from the Paris Agreement, some politicians are taking a stand and making their own commitments to fight climate change.

Hawaii has become the first state to sign into law the commitments and goals of the Paris climate accord, which calls for countries to reduce greenhouse gas emissions and invest in “green” technology in the hope of slowing the effects of global warming. Hawaii Gov. David Ige signed two bills yesterday that will implement portions of the agreement.

Rising sea levels will boost moderate floods in some areas, severe floods in others

Rising seas are making flooding more common in coastal areas around the country. Now, a new study finds that sea-level rise will boost the occurrence of moderate rather than severe flooding in some regions of the United States, while in other areas the reverse is true.

The study by researchers at Princeton and Rutgers universities found that along the southeastern coast, where severe flooding due to hurricanes is relatively frequent, cities such as Charleston, South Carolina, will see a disproportionate increase in moderate flooding. However, areas that have little history of severe flooding, such as Seattle, are likely to experience a greater uptick in the number of severe, or even historically unprecedented, floods.

The study, published June 7 in the journal Environmental Research Letters, looked at how climate-driven sea-level rise is likely to amplify coastal flooding.

Global Warming

Hotter Cities

New research finds that a combination of global warming and localized heating due to the urban heat island (UHI) effect could cause some of the world’s cities to be as much as 14 degrees Fahrenheit warmer by the end of this century.

The UHI effect occurs as buildings, roadways and other man-made structures store far more heat than natural settings, especially after the sun goes down. This amplifies the local warming effects of climate change, according to a report published in the journal Nature Climate Change.

Scientists recommend painting roofs a reflective white and planting more trees to limit urban warming.

Global Warming

The Larsen C Iceberg Is on the Brink of Breaking Off

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The saga of the Larsen C crack is about reach its stunning conclusion. Scientists have watched a rift grow along one of Antarctica’s ice shelves for years. Now it’s in the final days of cutting off a piece of ice that will be one of the largest icebergs ever recorded.

It’s the latest dreary news from the icy underbelly of the planet, which has seen warm air and water reshape the landscape in profound ways.

The crack has spread 17 miles over the past six days, marking the biggest leap since January. It’s also turned toward where the ice shelf ends and is within eight miles of making a clean break. There’s not much standing in its way either.

“The rift has now fully breached the zone of soft ‘suture’ ice originating at the Cole Peninsula and there appears to be very little to prevent the iceberg from breaking away completely,” scientists monitoring the ice with Project MIDAS wrote on their blog.

Trump Pulls USA Out of Global Climate Change Pact

President Donald Trump is pulling the United States out of the Paris Agreement, a worldwide accord that was developed to curb rising global temperatures and limit climate change in the coming years.

“In order to fulfill my solemn duty to protect America and its citizens, the United States will withdraw from the Paris climate accord,” Trump said at a news conference on June 1.

The Paris Agreement is designed to slow global warming by reducing greenhouse gas emissions and by stepping up investments in “green” technology. Nearly 200 countries agreed on the deal in December 2015 and signed it in 2016. By working together, nations around the world are trying to keep the planet’s average temperature from rising more than 3.6 degrees Fahrenheit (2 degrees Celsius) above Earth’s average temperature during preindustrial times. However, the agreement has an even more ambitious goal: “to limit the temperature increase even further to 1.5 degrees Celsius [2 degrees F],” according to the United Nations.

The United States’ departure won’t cause the agreement to fall apart, but it will likely weaken it, especially if other countries follow suit. Moreover, countries that remain a part of the agreement might cooperate less with the United States in the future and, in a worst-case scenario, even impose carbon tariffs on the U.S., according to The New York Times.

Methane ‘blowout’

Giant craters on the Arctic sea floor were formed when methane gas previously trapped in ice was released with such force it blew through bedrock, Norwegian researchers say.

A study published in the latest edition of the journal Science says that during the last ice age, a sheet of ice up to two kilometres thick lay on the floor of the Barents Sea off Norway, holding vast amounts of methane in hydrate form — an ice-like mix of gas and water.

According to the researchers, when a warming climate caused the ice sheet to dissipate around 12,000 years ago, the methane concentrated in mounds and then was “abruptly released,” causing the craters.

Methane continues to seep out into the water to this day, Andreassen said, through more than 600 “gas flares” that remain near the craters.

Methane gas in northern waters is also an issue in Canada. This August 2009 photo shows methane gas bubbles in the Mackenzie River Delta in the Northwest Territories.

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Global Warming

Great Barrier Reef can no longer be saved

The Great Barrier Reef can no longer be saved in its present form partly because of the “extraordinary rapidity” of climate change, experts have conceded.

Like coral across the world, the reef has been severely damaged by the warming of the oceans with up to 95 per cent of areas surveyed in 2016 found to have been bleached.

Bleaching is not always fatal but a study last year found the “largest die-off of corals ever recorded” with about 67 per cent of shallow water coral found dead in a survey of a 700km stretch.

Now experts on a committee set up by the Australian government to improve the health of the reef have revealed that they believe the lesser target of maintaining its “ecological function” is more realistic.

The concept of ‘maintaining ecological function’ refers to the balance of ecological processes necessary for the reef ecosystem as a whole to persist, but perhaps in a different form, noting the composition and structure may differ from what is currently seen today.

Coral reefs

Global Warming

Early Collapse of Arctic Sea Ice

Earth’s already-beleaguered northern icecap suffered another blow this month with the early collapse of a barrier that kept some of Arctic’s most durable ice in place.

The ice arch across the Nares Strait, which separates Greenland from Ellesmere Island in Canada’s far northeast, gave way two months earlier than usual, said Laurence Dyke, a paleoglaciologist at the Geological Survey of Denmark and Greenland.

“On May 10, this arch disintegrated, leaving the oldest and thickest sea ice in the Arctic vulnerable to being swept south where it will melt away,” Dyke told Seeker. “Over the last two weeks, the area of broken ice has expanded massively to the north, and lots of Arctic sea ice is flowing southwards through the Nares Strait.”

The channel and the Lincoln Sea, at the northern tip of Greenland, are normally covered by a sheet of ice several meters thick until around July, Dyke said. Usually, ice sheets that cover the strait are anchored to land and don’t move, blocking the passage of sea ice through the strait.

But as heat-trapping fossil-fuel emissions like carbon dioxide build up in the atmosphere, the Arctic is warming twice as fast as the rest of the globe. And this year, land-anchored ice in the strait failed to form amid the record warmth and record low sea ice coverage recorded across the Arctic. That left only an arch of ice at the northern end of the strait, where it joined the Lincoln Sea — the structure that gave way earlier this month.

“This is especially important as the Lincoln Sea contains the last bastion of old, thick multi-year sea ice,” Dyke said.

This image shows the boundary between permanent and seasonal sea ice in the Arctic Ocean, northwest of Greenland

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Global Warming

US growing season extends by 13 frost-free days

The number of frost-free days in the northern United States has increased by more than 13 days in the past 100 years, according to new research.

The other main areas of the mainland US also saw significant increases in the number of days without frost, essentially the growing season – 10.7 days in the west, 8.6 in a central region and 7.7 days in the south.

Global warming was one of the reasons for the trend, but the researchers also found changes to local cloud cover and atmospheric circulation patterns played a part.

Global Warming

Antarctica is going green – not in a good way

Plant life is growing on Antarctica like never before in modern times, fueled by global warming which is melting ice and transforming the landscape from white to green.

Scientists studying moss in an area spanning 400 miles (640 kilometers) have found a sharp increase in growth over the past 50 years, said the report in the journal Current Biology.

Plant life exists on only about 0.3 percent of Antarctica.

Five moss cores — or column-like samples drilled from the Earth — showed evidence of what scientists called “changepoints,” or points in time after which biological activity clearly increased.

Areas sampled included three Antarctic islands — Elephant Island, Ardley Island, and Green Island — where the deepest and oldest moss banks grow, said the report.

The polar regions are warming more rapidly than the rest of the Earth, as greenhouse gasses from fossil fuel burning build up in the atmosphere and trap heat.

The Arctic is warming the fastest, but Antarctica is not far behind, with annual temperatures gaining almost one degree Fahrenheit (half degree Celsius) each decade since the 1950s.

“The sensitivity of moss growth to past temperature rises suggests that ecosystems will alter rapidly under future warming, leading to major changes in the biology and landscape of this iconic region,” said researcher Dan Charman, a professor at Exeter.

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Global Warming

American Trees Are Moving West Due to Climate Change

As the consequences of climate change strike across the United States, ecologists have a guiding principle about how they think plants will respond. Cold-adapted plants will survive if they move “up”—that is, as they move further north (away from the tropics) and higher in elevation (away from the warm ground).

A new survey of how tree populations have shifted over the past three decades finds that this effect is already in action. But there’s a twist: Even more than moving poleward, trees are moving west.

About three-quarters of tree species common to eastern American forests—including white oaks, sugar maples, and American hollies—have shifted their population center west since 1980. More than half of the species studied also moved northward during the same period.

These results, among the first to use empirical data to look at how climate change is shaping eastern forests, were published in Science Advances on Wednesday.

Trees, of course, don’t move themselves. But their populations can shift over time, and saplings can expand into a new region while older growth dies in another.

While climate change has elevated temperatures across the eastern United States, it has significantly altered rainfall totals. The northeast has gotten a little more rain since 1980 than it did during the proceeding century, while the southeast has gotten much less rain. The Great Plains, especially in Oklahoma and Kansas, get much more than historically normal.

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