How trees affect the weather

Nature, said Ralph Waldo Emerson, is no spendthrift. Unfortunately, he was wrong.

New research led by University of Utah biologists William Anderegg, Anna Trugman and David Bowling find that some plants and trees are prolific spendthrifts in drought conditions -- "spending" precious soil water to cool themselves and, in the process, making droughts more intense. The findings are published in Proceedings of the National Academy of Sciences.

"We show that the actual physiology of the plants matters," Anderegg says. "How trees take up, transport and evaporate water can influence societally important extreme events, like severe droughts, that can affect people and cities."

Functional traits

Anderegg studies how tree traits affect how well forests can handle hot and dry conditions. Some plants and trees, he's found, possess an internal plumbing system that slows down the movement of water, helping the plants to minimize water loss when it's hot and dry. But other plants have a system more suited for transporting large quantities of water vapor into the air -- larger openings on leaves, more capacity to move water within the organism. Anderegg's past work has looked at how those traits determine how well trees and forests can weather droughts. But this study asks a different question: How do those traits affect the drought itself?

"We've known for a long time that plants can affect the atmosphere and can affect weather," Anderegg says. Plants and forests draw water out of the soil and exhale it into the atmosphere, affecting the balance of water and heat at our planet's surface, which fundamentally controls the weather. In some cases, like in the Amazon rainforest, all of that water vapor can jumpstart precipitation. Even deforestation can affect downwind weather by leaving regions drier than before.

Anderegg and his colleagues used information from 40 sites around the world, in sites ranging from Canada to Australia. At each site, instruments collected data on the flows of heat, water and carbon in and out of the air, as well as what tree species were prevalent around the instrumentation. Comparing that data with a database of tree traits allowed the researchers to draw conclusions about what traits were correlated with more droughts becoming more intense.

Two traits stuck out: maximum leaf gas exchange rate and water transport. The first trait is the rate at which leaves can pump water vapor into the air. The second describes how much water the tree can move to the leaves. The results showed that in cool regions, plants and trees slowed down their water use in response to declining soil moisture. But in hot climates, some plants and trees with high water transport and leaf gas exchange rates cranked up the AC, so to speak, when the soil got dry, losing more and more water in an effort to carry out photosynthesis and stay cool while depleting the soil moisture that was left.

"You end up getting to these conditions that are hotter and drier much faster with those plants than with other plants," Anderegg says.

More drought to come

It's true that hot and dry regions tend to have more plants and trees that are adapted to dry conditions. But regardless of the climate some species with water-intensive traits, such as oaks in a Mediterranean climate, can still exacerbate a drought.

Anderegg says that understanding the relationship between a tree's traits and drought conditions helps climate scientists and local leaders to plan for future drought effects on communities.

"Failing to account for this key physiology of plants would give us less accurate predictions for what climate change is going to mean for drought in a lot of regions," he says.

Drought is always on Anderegg's mind, even during the recent wet spring. "Just because we're having a good water year in the U.S. and in Utah this year doesn't get us off the hook," he says. "We need to remember that we're going to see a lot more droughts in the future."

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Materials provided by University of Utah. Note: Content may be edited for style and length.


Desertification Threatens Millions of People, UN Says

The UN Secretary-General, Antonio Guterres, has warned on Monday that desertification, land degradation and drought are pivotal threats affecting millions of people globally.

In his message for the World Day to Combat Desertification and Drought, Guterres stressed these problems have a greater impact on women and children.

Twenty-five years ago, 197 nations passed a historic agreement to mobilize global action to combat desertification, but much remains to be done, Guterres stated.

According to him, the world loses 24 billion tons of fertile soil every year, and the drylands and land degradation scale down the gross domestic product (GDP) in developing countries by up to 8 percent per year.

We urgently need to change such trends, Guterres said, referring to the fact that protection and better use of land can reduce forced migration, enhance food safety and boost economic growth.

It can also help us deal with global climate emergency, he pointed out.

On this World Day to Combat Desertification and Drought, Guterres called for, we recognize how imperative is to combat this problem as part of common efforts to Sustainable Development Goals.

Desertification Threatens Millions of People, UN Says

United Nations, June 17 (Prensa Latina) The UN Secretary-General, Antonio Guterres, has warned on Monday that desertification, land degradation and drought are pivotal threats affecting millions of people globally.

In his message for the World Day to Combat Desertification and Drought, Guterres stressed these problems have a greater impact on women and children.

Twenty-five years ago, 197 nations passed a historic agreement to mobilize global action to combat desertification, but much remains to be done, Guterres stated.

According to him, the world loses 24 billion tons of fertile soil every year, and the drylands and land degradation scale down the gross domestic product (GDP) in developing countries by up to 8 percent per year.

We urgently need to change such trends, Guterres said, referring to the fact that protection and better use of land can reduce forced migration, enhance food safety and boost economic growth.

It can also help us deal with global climate emergency, he pointed out.

On this World Day to Combat Desertification and Drought, Guterres called for, we recognize how imperative is to combat this problem as part of common efforts to Sustainable Development Goals.

  • Published in World

Delhi Recorded an All-Time High Temperature at 48 Degrees Celsius

New Delhi temperature broke record, when the mercury touched a historical maximum of 48 degrees Celsius in parts of the national capital.

The severe heat waves continue affecting north and central India, with record high temperatures in many cities.

In Uttar Pradesh, Banda was the hottest area on Monday at 49.2 degrees Celsius, seven degrees above normal. In Churu, Rajasthan, temperature recorded at 50.3 degrees Celsius and the Medical Department issued a warning not to go outside, except in emergency situations.

The southwest winds for Tuesday can make the temperature drop one or two marks. However, the heat wave will persist, the Indian Meteorological Department (IMD) regional weather forecasting chief, Kuldeep Srivastava, said.

Meteorologists declare a heat wave in large areas when the mercury touches 45 degree Celsius for two consecutive days and a severe heat wave is declared when the temperature rises to 47 degrees Celsius for two days.

For small areas, such as New Delhi, a heat wave is declared if the maximum temperature is recorded at 45 degrees Celsius even for one day, the IMD said.

  • Published in World

Research predicts extreme fires will increasingly be part of our global landscape

Increasingly dangerous fire weather is forecast as the global footprint of extreme fires expands, according to the latest research.

University of Tasmania Professor of Environmental Change Biology David Bowman led an international collaboration - including researchers from the University of Idaho and South Dakota State University - to compile a global satellite database of the intensity of 23 million landscape fires between 2002 and 2013.

Of the 23 million fires, researchers honed in on 478 of the most extreme wildfire events.

"Extreme fire events are a global and natural phenomenon, particularly in forested areas that have pronounced dry seasons," Professor Bowman said.

"With the exception of land clearance, the research found that extremely intense fires are associated with anomalous weather - such as droughts, winds, or in desert regions, following particularly wet seasons.

"Of the top 478 events we identified 144 economically and socially disastrous extreme fire events that were concentrated in regions where humans have built into flammable forested landscapes, such as areas surrounding cities in southern Australia and western North America."

Using climate change model projections to investigate the likely consequences of climate change, the research found more extreme fires are predicted in the future for Australia's east coast, including Brisbane, and the whole of the Mediterranean region - Portugal, Spain, France, Greece and Turkey.

"The projections suggest an increase in the days conducive to extreme wildfire events by 20 to 50 per cent in these disaster-prone landscapes, with sharper increases in the subtropical Southern Hemisphere, and the European Mediterranean Basin," Professor Bowman said.

University of Idaho Assistant Professor Crystal Kolden said the United States had a much higher proportion of fire events become disasters than any other country in the study. Wildfire burned more than 10 million acres in the US in 2015, and cost over $2 billion to suppress.

"What is really novel about this study is that in the US, we tend to make the assumption that all large and intense fires are disasters, and that there is nothing we can do about it," Assistant Professor Kolden said.

"The projections suggest an increase in the days conducive to extreme wildfire events by 20 to 50 per cent in these disaster-prone landscapes, with sharper increases in the subtropical Southern Hemisphere, and the European Mediterranean Basin," Professor Bowman said.

University of Idaho Assistant Professor Crystal Kolden said the United States had a much higher proportion of fire events become disasters than any other country in the study. Wildfire burned more than 10 million acres in the US in 2015, and cost over $2 billion to suppress.

"What is really novel about this study is that in the US, we tend to make the assumption that all large and intense fires are disasters, and that there is nothing we can do about it," Assistant Professor Kolden said.

Read more at: https://phys.org/news/2017-02-extreme-increasingly-global-landscape.html#jCp

University of Tasmania Professor of Environmental Change Biology David Bowman led an international collaboration - including researchers from the University of Idaho and South Dakota State University - to compile a global satellite database of the intensity of 23 million landscape fires between 2002 and 2013.

Of the 23 million fires, researchers honed in on 478 of the most extreme wildfire events.

"Extreme fire events are a global and natural phenomenon, particularly in forested areas that have pronounced dry seasons," Professor Bowman said.

"With the exception of land clearance, the research found that extremely intense fires are associated with anomalous weather - such as droughts, winds, or in desert regions, following particularly wet seasons.

"Of the top 478 events we identified 144 economically and socially disastrous extreme fire events that were concentrated in regions where humans have built into flammable forested landscapes, such as areas surrounding cities in southern Australia and western North America."

Using model projections to investigate the likely consequences of climate change, the research found more extreme fires are predicted in the future for Australia's east coast, including Brisbane, and the whole of the Mediterranean region - Portugal, Spain, France, Greece and Turkey.

Read more at: https://phys.org/news/2017-02-extreme-increasingly-global-landscape.html#jCp

University of Tasmania Professor of Environmental Change Biology David Bowman led an international collaboration - including researchers from the University of Idaho and South Dakota State University - to compile a global satellite database of the intensity of 23 million landscape fires between 2002 and 2013.

Of the 23 million fires, researchers honed in on 478 of the most extreme wildfire events.

"Extreme fire events are a global and natural phenomenon, particularly in forested areas that have pronounced dry seasons," Professor Bowman said.

"With the exception of land clearance, the research found that extremely intense fires are associated with anomalous weather - such as droughts, winds, or in desert regions, following particularly wet seasons.

"Of the top 478 events we identified 144 economically and socially disastrous extreme fire events that were concentrated in regions where humans have built into flammable forested landscapes, such as areas surrounding cities in southern Australia and western North America."

Using model projections to investigate the likely consequences of climate change, the research found more extreme fires are predicted in the future for Australia's east coast, including Brisbane, and the whole of the Mediterranean region - Portugal, Spain, France, Greece and Turkey.

Read more at: https://phys.org/news/2017-02-extreme-increasingly-global-landscape.html#jCp

University of Tasmania Professor of Environmental Change Biology David Bowman led an international collaboration - including researchers from the University of Idaho and South Dakota State University - to compile a global satellite database of the intensity of 23 million landscape fires between 2002 and 2013.

Of the 23 million fires, researchers honed in on 478 of the most extreme wildfire events.

"Extreme fire events are a global and natural phenomenon, particularly in forested areas that have pronounced dry seasons," Professor Bowman said.

"With the exception of land clearance, the research found that extremely intense fires are associated with anomalous weather - such as droughts, winds, or in desert regions, following particularly wet seasons.

"Of the top 478 events we identified 144 economically and socially disastrous extreme fire events that were concentrated in regions where humans have built into flammable forested landscapes, such as areas surrounding cities in southern Australia and western North America."

Using model projections to investigate the likely consequences of climate change, the research found more extreme fires are predicted in the future for Australia's east coast, including Brisbane, and the whole of the Mediterranean region - Portugal, Spain, France, Greece and Turkey.

Read more at: https://phys.org/news/2017-02-extreme-increasingly-global-landscape.html#jCp

NASA spots Tropical Storm Howard developing in Eastern Pacific

Infrared data from NASA's Aqua satellite showed strong thunderstorms within the ninth tropical depression of the Eastern Pacific Ocean, as the storm was strengthening. Early on Aug. 1 Tropical Depression 9E intensified into a tropical storm and was renamed Howard.

Tropical Storm Howard, the ninth tropical cyclone to develop in 30 days in the Eastern Pacific is also the eighth named storm of the 2016 season. Tropical Depression 1E in June was the only tropical cyclone that developed this season and did not reach status.

On July 31, at 5:05 p.m. EDT (9:05 p.m. UTC) the Atmospheric Infrared Sounder or AIRS instrument aboard NASA's Aqua satellite captured on Tropical Depression 9E. The AIRS data showed that the coldest cloud top temperatures of at least minus 63 F (minus 53 C) and strongest thunderstorms circled the low-level center with the exception of the northern quadrant of the storm. Strong storms also fed into the low level center from a band of thunderstorms southwest of the center.

Over the course of 12 hours, the cloud pattern of the cyclone improved. At 5 a.m. EDT (9: a.m. UTC) on Aug. 1, the depression became a tropical storm. At that time, Tropical Storm Howard's maximum sustained winds were near 40 mph (65 kph) with higher gusts. The center of Tropical Storm Howard was located near 16.1 degrees north latitude and 122.9 degrees west longitude, about 965 miles (1,555 km) west-southwest of the southern tip of Baja California, Mexico. Since Howard is far enough away from land areas there are no coastal watches or warnings in effect.

The National Hurricane Center NHC said that Howard was moving toward the west-northwest near 10 mph (17 kph) and this general motion is expected to continue for the next couple of days. The estimated minimum central pressure was 1,005 millibars.

The NHC forecast indicated that some additional strengthening is forecast today and Tuesday morning. Then, gradual weakening is expected to begin by Tuesday night and Wednesday when Howard moves over cooler water.

2 planes collide at Minsk Airport due to stormy weather

Several planes have been damaged by a storm at the airport in the capital of Belarus, with two aircraft colliding on the airfield. There have been no reports of injuries.

The planes that collided belong to the Belarusian Belavia Airlines and the Ruby Star Air Carrier Company, pictures posted on social media show. Belavia officials have already confirmed to the local media that the company’s airplanes were hit by the storm.

“There are problems in the airport because of the storm,” a Belavia representative told Belorussian Tut.by news portal, adding that “some aircraft are damaged, including ours.”

"There are no dead or injured from the incident,” the company representatives added.

There were no passengers onboard the two planes that collided, the Belavia press service told journalists.

The airport press service said that several windows in the airport terminal had been smashed and a suspended ceiling system was deformed in several places due to rough wind and heavy rains.

Several flights were also re-routed to alternate airport in the Belorussian city of Gomel, and another was re-routed to the city of Vilnius in neighboring Lithuania.

The airport now is now operating as usual, the press service added.

  • Published in World
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