Posts

2017 Was a Really Bad Year for Tropical Forests

D6665759-FEF3-4E18-818DBB262E86051D

Tropical forests suffered some of their worst losses in history last year, according to a new report from the monitoring group Global Forest Watch.

About 39 million acres, or 61,000 square miles, of forest cover disappeared in 2017—an area approximately the size of Bangladesh. That makes it the second-worst year on record, topped only by losses in 2016.

It’s discouraging news for global climate mitigation efforts. Healthy tropical forests store vast amounts of carbon, while deforestation can release that carbon back into the atmosphere.

And research suggests declines in tropical forest cover are taking their toll: Last year, a blockbuster study in Science concluded that tropical forests—because of their widespread destruction—are actually a net source of carbon to the atmosphere, rather than a carbon sink, as many experts had previously assumed.

The new data present “an alarming story of the situation for the world’s rainforests”, Andreas Dahl-Jørgensen, deputy director of Norway’s International Climate and Forest Initiative, said during a teleconference announcing the findings. “We simply won’t meet the climate targets that we agreed [to] in Paris without a drastic reduction in tropical deforestation and restoration of forests around the world.

The findings were released yesterday morning as representatives from around the world convened in Oslo, Norway, for an international forum on conserving tropical forests. A major focus of the conference includes the role of forests in global climate action.

Several recent estimates have underscored the significant contributions of deforestation to global carbon output—both the 2017 Science paper and a more recent estimate from the Global Carbon Project have suggested that forest losses and degradation may account for more than 10 percent of the world’s emissions.

But while the potential of forests to store or emit carbon remains their most substantial role in global climate efforts, some scientists note that forest losses may influence climate in other ways, as well. A new report from the World Resources Institute, also released this week to coincide with the Oslo forum, points out that deforestation can affect local temperatures and even alter the local water cycle. The report cites a range of recent studies on these effects.

Tree cover, for instance, has the potential to either warm or cool a local climate, depending on a combination of factors. On the one hand, trees tend to be darker in color than their surroundings, meaning they absorb more sunlight and more heat. On the other hand, they also release water into the air through their leaves, and they help to break up landscapes in ways that can disperse heat—both factors that may cool the local climate. Trees also release certain chemical compounds into the atmosphere that can have either cooling or warming effects.

But some recent research suggests that the cooling effect of trees may win out—meaning deforestation can drive local temperatures up and exacerbate the influence of ongoing climate change. A paper published in Nature Climate Change in April, for instance, links deforestation in the Northern Hemisphere to an increase in the intensity of hot days throughout the year.

Overall, the study suggests that deforestation probably accounted for more than half the warming that occurred over North America between 1920 and 1980. This effect has now been outstripped by the growing influence of human-caused climate change, but the researchers say deforestation may still account for nearly a third of the region’s warming (Climatewire, April 24).

2016 paper in Science had a similar message, suggesting forest losses around the world generally drive local temperatures higher. In fact, on a global average, it suggests the warming they produce may be the equivalent of about 18 percent of the influence from human-caused greenhouse gas emissions.

Other research suggests that deforestation could affect regional precipitation patterns. Trees lose water through their leaves, putting moisture back into the air—so tree cover losses can lead to drier local climates.

The effect may be particularly pronounced in tropical rainforests. One 2015 study found that deforestation in the Amazon basin reduces the region’s rainfall—and suggests that if the current deforestation rate continues, average rainfall throughout the Amazon basin could decline by more than 8 percent by 2050.

The point, the WRI report notes, is that “tropical forest loss is having a larger impact on the climate than has been commonly understood.”

Deforestation and degradation contribute substantially to global carbon emissions, thus helping fuel the progression of human-caused climate change. And at the same time, other non-carbon climate effects of deforestation may also be compounding the influence of global warming.

“When you add up these impacts of forest loss, one thing is clear: People living closest to deforested areas face a hotter, drier reality,” said Nancy Harris of WRI, who co-authored the report with Michael Wolosin of Forest Climate Analytics.

The new findings from the Global Forest Watch add renewed urgency to the global conversation on forest conservation and its role in international climate mitigation.

“A lot is hinging on our success in reversing these trends,” Dahl-Jørgensen said.

Source: scientificamerican.com

(Dipla Aikaterini)

Climate Change Could Lead to Major Crop Failures in World’s Biggest Corn Regions

child-with-corn_mohammed-abeda-afp-getty_0

Climate change will increase the risk of simultaneous crop failures across the world’s biggest corn-growing regions and lead to less of the nutritionally critical vegetables that health experts say people aren’t getting enough of already, scientists warn.

Two new studies published in Proceedings of the National Academy of Sciences look at different aspects of the global food supply but arrive at similarly worrisome conclusions that reiterate the prospects of food shocks and malnutrition with unchecked global warming. While developing tropical countries would likely be hardest hit, the destabilizing financial effects could reach all corners of the globe, the authors say.

One paper analyzed corn—or maize—the world’s most produced and traded crop, to project how climate change will affect it across the major producing regions. Much of the world’s corn goes into feeding livestock and making biofuels, and swings in production can ripple through global markets, leading to price spikes and food shortages, particularly for the 800 million people living in extreme poverty.

The researchers found significant differences in corn yield depending on how high global temperatures rise.

An increase of 4 degrees Celsius—close to where the current greenhouse gas emissions trajectory would take us by the end of this century—could cut U.S. corn production by nearly half. If global warming is instead held to 2°C (the goal of the Paris climate agreement is to stay below that level) the projected loss in U.S. production would be closer to 18 percent, the researchers found.

Chart: Global warming increases risks to corn yields

Risk of Simultaneous Crop Failures Rises

While those numbers are pretty dramatic, the researchers find that the chances of the top-producing regions suffering extreme yield losses at the same time rises, too.

When the researchers looked at the four biggest corn exporters—the U.S., Brazil, Argentina and Ukraine—they found that the likelihood of all four suffering yield losses of 10 percent or more at the same time rises from about 7 percent at 2°C warming to 86 percent at 4°C warming.

Such simultaneous shocks in the top-producing regions, which are rare now, could have significant impacts on global markets and drive up the price of food.

“Global grain prices have been going up because of demand and biofuels,” said Michelle Tigchelaar, the lead author of the study and a researcher with the University of Washington. “That has made markets tighter, so when you have a yield shock, that has really big implications for the market.”

And for global stability. During the last global food crisis, in 2007 and 2008, rising costs triggered riots and unrest in countries around the world.

Vegetables also at Risk from Global Warming

The second study published Monday looked at how environmental changes brought on by climate change could impact the production and quality of vegetables and legumes—foods that government nutrition guidelines and nutritionists urge people to eat more of.

Researchers led by the London School of Hygiene & Tropical Medicine looked at 174 studies, across 40 countries, published since 1975. The authors say it is the first attempt to systematically examine how climate-induced environmental changes could impact yields of vegetables and legumes around the world.

While previous research has shown that increased levels of carbon dioxide could boost some vegetable and legume yields, the new study finds that any benefits will be offset by the negative effects of increased ozone, less water availability and increased salinity.

Nutritionally important vegetables and legumes can be particularly sensitive to temperature increases and more vulnerable to heat stress than staple or cereal crops. The researchers found that without efforts to reduce emissions, a lack of water and increased ozone would cut yields of vegetables by about 35 percent in the second half of this century.

Result: People Lose Key Sources of Nutrition

Globally, about 2 billion people suffer from micronutrient deficiencies linked to a lack of vegetable and legume consumption, while worldwide per capita consumption of vegetables and fruits is between 20 and 50 percent below recommended levels.

Vegetables and legumes are vital components of a healthy, balanced and sustainable diet and nutritional guidelines consistently advise people to incorporate more vegetables and legumes into their diet,” said Pauline Scheelbeek, the lead author of the study. “Our new analysis suggests, however, that this advice conflicts with the potential impacts of environmental changes that will decrease the availability of these important crops unless action is taken.”

Another recent study that analyzed the impact of climate change on rice, a primary food source for 2 billion people, found that rising carbon dioxide levels will also diminish its nutrient levels.

Source: insideclimatenews.org

(Dipla Aikaterini)

New study examines impacts of fracking on water supplies worldwide

1-newstudyexam
Using hydraulic fracturing to extract oil and natural gas from shale is a common technique used worldwide. Because the technique requires large amounts of water, however, it raises the question of whether it could lead to water shortages or competition with other water uses, especially agriculture.

In a new paper in the AGU journal Earth’s Future, Lorenzo Rosa and his colleagues evaluated the impacts of on local availability for food production and other human and environmental needs globally.

They found that 30 percent of shale deposits are located in arid regions where aquifers are already being heavily tapped for irrigating crops and 31 percent to 40 percent of shale deposits are in areas where water-stress would emerge or be exacerbated by fracking.

The researchers conclude that in such places water management plans would be needed to ensure that fracking would not affect other human and environmental water needs.

The map shows water stress within shale deposits. In water stressed areas, water is consumed at greater rates than the local water supply is replenished. Green, yellow, orange or red pixels represent areas where there are shale deposits and where freshwater is already being used at unsustainable rates. Areas with water stress indexes greater than one are where consumption for human activities is unsustainable.

Source: phys.org

(Dipla Aikaterini)

‘Water is life’: Ivory Coast city struggles with crippling drought

anivorianwom
“All that comes out of the tap right now is cockroaches,” said Honorine Babalou, a 20-year-old textile worker.

In Bouake, Ivory Coast’s second city, the regular supply trickled to a halt three months ago—a shortage that officials blame on a drought inflicted by global warming.

Like many other Bouake residents, Babalou balanced on her head a giant basin of fresh water drawn from a tanker truck which had trundled down sun-scorched clay tracks to make a delivery in a poor part of town.

The city of about 800,000 people, as estimated by the mayor, has long depended on the nearby Loka dam for around three-quarters of its water supply.

But the lake behind the dam has shrivelled to almost nothing. Hundreds of metres (yards) behind a sign that sternly declares “Fishing and Bathing Forbidden” lies a sad, muddy puddle.

This is . It rains a lot less often, the sun has been stronger for several years,” states Yeboue Ouffoue, 85, chief of the small village of Angoua-Yaokro, near the site where the dam was built in the late 1970s.

“Here we live off agriculture, but with the water shortage we can no longer plant the way we want. Income has dropped, that’s for sure,” Ouffoue said, expressing concern for some 300 villagers in his charge. “Times are hard.”

“We’ve entered a time of water rationing in Bouake,” said Mayor Nicolas Djibo, who also blames climate change, along with people who diverted waterways to exploit sand quarries in the region.

Young Ivorian women carrying precious water in the city where the taps have run dry

‘Greeted like the Messiah’

Located in the centre of Ivory Coast, Bouake is known as a centre for “white gold”, referring to the once lucrative cotton industry, and now “grey gold”, the thriving cashew nut business.

The city formerly served as headquarters for rebels who helped bring President Alassane Ouattara to power in 2011 after a disputed election and a violent political crisis.

Today, faced with an existential threat, the city is looking at a scheme to pipe in supplies from Lake Kossou, about 100 kilometres (60 miles) away.

This operation would take two years and cost an estimated 45 million euros ($53 million), said Djibo, who hopes the World Bank will help finance it.

At the Alassane Ouattara 2 University in Bouake, the lack of water has forced many students to leave their rooms on campus to return home, some geography students told AFP.

Tanker trucks now provide emergency supplies, after attempts to drill into groundwater faltered. In a bid to ease the shortage, authorities sank wells in several parts of Bouake, but the water pumped fell far short of basic requirements.

“We’re greeted like the Messiah, or something like that,” joked driver Mohamed Lamine Diakite, whose truck carries 10,000 litres (2,500 gallons) of water. He announces his arrival in a district by pumping his horn to bring local residents running.

A supplier distributes water from a tanker truck to residents of Bouake at the start of July 2018

In the Sokoura district, women set out hundreds of basins and buckets on the ground, waiting for the water distribution under a broiling sun. There are few men around. Women carry away the heavy load for the family.

‘Water is like treasure’

“We cannot live like this,” said Mariam Kone, a trading woman with three children who also cares for her sick mother.

“You can go two or three days without washing yourself. Before this, we drank water straight from the tap. Today, we adults hold back but the children don’t understand. We have to pay for mineral water. The price has risen by 400 (CFA francs) to 800 (1.20 euros, $1.40). We’re spending more and more—we’ll go broke,” Kone said.

People in the 2 Bodjo district make similar protests. “This is too hard. This doesn’t suit us. We have no water to wash or to drink. When the truck doesn’t come, we have to take water from the well or swamps,” said Chigata Soro, 30, who sells hot food at the roadside. “We need water. It’s not too much to ask.”

Others are angry at officialdom, accusing it of mismanaging both the problem and the solution.

“They tell us ‘It’s emergency measures’ or ‘Wait a couple of years’ but the dam didn’t go dry from one day to the next. The government, the authorities, the (water distribution company) SODECI—somebody handled this really badly,” one resident said.

Awaiting her turn in line, Sabine Kone yelled at a neighbour: “Hands off my water!”

Explaining her sharp words, the young student said: “Water is like treasure now. And what’s more, she wanted to fill her dirty flask from my bowl. This water we get is drinking water. She was going to make it dirty. Water is life!

Source: phys.org

(Dipla Aikaterini)

International Environment Day: Plastic in Africa

plasticprobl
This year, plastic pollution is the main theme of International Environment Day, celebrated on June 5.

In Africa, 4.4 million tonnes of plastic are found in oceans and seas every year, according to United Nations figures from 2010.

Plastic, and in general, is a very big problem in Africa,” said Mohamed Atani, regional information officer for the UN environmental agency UNEP.

Discarded plastic is a biohazard that can take decades to degrade. But at this site in Kampala, Uganda, women clean plastic bags

He described the problem of , which is gaining attention globally as it kills and blankets swathes of the ocean surface, as “a danger for human health”.

“Most of the plastic disposed in the ocean comes from the daily use of single-use plastics,” said Atani.

Spoiled seas: Plastic comprises most of the debris washed up on a beach near the South African city of Cape Town, whose fabled T

The European Union this month proposed a ban on items such as plastic straws and cutlery.

While many western nations still dole out plastic bags in supermarkets, several African countries have taken the lead and banned them entirely, such as Morocco, Rwanda and Kenya.

Source: phys.org

(Dipla Aikaterini)

Climate change hits poorest hardest, new research shows

64-climatechang
Australia will still be the lucky country when it comes to changes in local climate as a result of climate change if global average surface temperatures reach the 1.5°C or 2°C limit set by the Paris agreement.

But in other countries right across the tropics, including close neighbour and major trading partner Indonesia, the heat of change hits hardest.

That is the finding of a new paper published today in Geophysical Research Letters, by a researcher from the ARC Centre of Excellence for Climate Extremes, which compares the difference between for wealthy and poor nations.

University of Melbourne climate research and study lead author Andrew King said the results are a stark example of the inequalities that come with global warming.

The richest countries that produced the most emissions are the least affected by heat when average temperatures climb to just 2°C, while poorer nations bear the brunt of changing local climates and the consequences that come with them,” Dr King said.

The research shows that the least affected countries include the most temperate nations such as the United Kingdom. By contrast, the worst affected are in the Equatorial regions, with the Democratic Republic of Congo among those feeling the heat most of all.

This pattern holds true even if global average surface temperatures only reach 1.5°C above pre-industrial levels.

To get their results the researchers used a simple metric – the signal to noise ratio. The signal in this case is the local change in average temperatures caused by climate change. The noise is how variable the is for that region.

In places outside the tropics, where there is greater year-to-year variability and those locations are more well adapted to a wide range of temperatures, the warming will be less noticeable.

But in Equatorial regions, where there is already a very high average temperature and less variation through the year, a small rise in temperatures due to climate change will be distinctly felt and have immediate impacts.

The researchers said this difference in experienced temperature combined with the distribution of wealth across the world, with richer nations tending to be in temperate regions and the poorer nations in the tropics, adds to the future climate change burden of developing nations.

“Economically powerful nations, who are most responsible for the emissions that led to , are going to have to pick up the slack if they want to maintain economic growth in developing countries,” said University of Oxford co-author Luke Harrington.

“It’s why we need to invest in limiting the worst impacts of for developing nations today,” Dr Harrington said.

“By assisting developing nations to meet these challenges we help maintain their economic stability and security into the future and by extension, our own as well.”

Source: phys.org

(Dipla Aikaterini)

WWF: Majority of Greek Islanders Open to Renewable Energy Systems

wwf

The residents of 15 Greek islands want to revert to renewable energy sources, according to a study carried out by WWF Greece as part of the ongoing TILOS (Technology Innovation for the Local Scale Optimum Integration of Battery Energy Storage) project.

Of those surveyed, 41 percent said they think RES (renewable energy systems) will have a positive impact on tourism.

The survey was carried out on the islands of Agios Efstratios, Astypalea, Anafi, Donoussa, Kastellorizo, Amorgos, Symi, Nisyros, Chalki, Milos, Sifnos, Rhodes, Santorini, Skyros and Ikaria – which due to size and location can benefit from the experience gained on Tilos, which was the first in Greece and the Mediterranean – in May last year – to run completely on a renewable energy-based battery station and smart micro-grid.

The majority of islanders – 73.7 percent – said they prefer RES for their needs. Respondents also said they would install photovoltaic (42 percent) or battery systems (49.3 percent) at their homes. At the same time, 32 percent said they do not consider wind turbines to be disturbing.

The aim of the study was to look into the possibility of applying the Tilos energy model – a hybrid energy production and storage station covering 85 percent of the island’s energy needs while also providing neighboring Kos with 400kW in power five hours a day – to other Aegean islands.

The Dodecanese island of Tilos won out of 12 nominees the EU Sustainable Energy Award in the Energy Islands category and the Citizens’ Award via public online vote last year for the TILOS application.

Source: news.gtp.gr

(Dipla Aikaterini)

Streams may emit more carbon dioxide in a warmer climate

streamsmayem
Streams and rivers could pump carbon dioxide into the air at increasing rates if they continue to warm, potentially compounding the effects of global warming, a new worldwide analysis has shown.

To reach that conclusion, an international research team conducted the first continental-scale study of flows into and out of streams across six major climatic zones. They collected data in watersheds from Puerto Rico and Oregon to Australia and Alaska. In each one, scientists analyzed the balance between photosynthesis—which uses atmospheric CO2 to generate plant material such as roots and leaves—and respiration, which pumps CO2 back into the air.

The scientists published their results this week in the journal Nature Geoscience.

The issue is important because the world’s rivers and streams exchange carbon with the atmosphere at rates that are comparable with land-based ecosystems and the oceans. If continues, an increase in stream-based carbon emissions could add to the concentration of heat-trapping CO2 in the atmosphere.

“This paper is the first to look at the effects of climate change on stream metabolism at the continental scale using field observations,” said Alba Argerich, co-author who monitored McRae Creek and Lookout Creek in the H. J. Andrews Experimental Forest east of Eugene, Oregon. “This approach takes into consideration the complexity of an ecosystem, as opposed to controlled experiments where you recreate simplified versions of an ecosystem.”

Argerich and other scientists monitored streams for water temperature, dissolved oxygen and sunlight at the water surface. The researchers also simulated the balance between net primary production (the product of photosynthesis by all organisms in the stream) and respiration under a 1-degree Celsius rise in stream temperature.

The net result of the simulations, they reported, was a 24 percent shift toward more respiration and CO2 emissions. However, not all streams are projected to respond in the same manner. The shift toward more CO2 emissions appears to be more pronounced in warmer streams, the scientists found, while colder streams might actually see an increase in net primary production. Carbon cycling in streams can also be affected by other factors such as the plants and microbes in the stream ecosystem and nutrients flowing into the water from surrounding lands.

Argerich conducted her work as a researcher in the College of Forestry at Oregon State University. She is now an assistant professor in the School of Natural Resources at the University of Missouri.

In previous work at the H.J. Andrews Forest, Argerich showed that small streams can export surprising amounts of carbon both downstream and to the atmosphere. “This paper confirms the role of streams as an active source of CO2 to the atmosphere, which can be even become more important as global temperatures increase,” she said.

Source: phys.org

(Dipla Aikaterini)

New research reveals ocean waves play greater role in trapping carbon dioxide

For decades scientists have investigated the influence of the world’s oceans in trapping greenhouse gasses. But a groundbreaking new study involving an academic from Heriot-Watt University has found waves play a greater role in this process than previously understood.

The research, published in Scientific Reports, shows that when waves break on the surface, such as in high winds, a substantial number of bubbles are injected to depths of at least one metre. These bubbles tend to partially dissolve, releasing into the water. The discovery means an increase in the current global estimates of the oceanic sink of carbon dioxide and rates of ocean acidification.

Led by the University of Southampton, the study was published in collaboration with UK-based scientists including Dr. David Woolf at Heriot-Watt’s Orkney Campus. He applied his expertise in modelling the processes of air-sea gas exchange for the project and said: “The role of bubbles in the air-sea exchange of gases has been of interest for decades, but firm conclusions have been prevented by a lack of adequate data. Participation in this project has been very rewarding since measurements are finally giving us the information we need.”

The results of the study, titled ‘Asymmetric transfer of CO2 across a broken sea surface’, indicate a much larger imbalance of carbon dioxide than previously suggested, contradicting an assumption inherent in most existing estimates of ocean atmosphere gas transfer.

The research could help the science community gain a stronger understanding of the influence of the ocean in contributing to global climate control.

Professor Tim Leighton, Principal Investigator for the study from the University of Southampton, said: “If the amount of carbon dioxide dissolving into the seas from the atmosphere exactly balanced the amount leaving the seas and entering the atmosphere, we would have a steady state situation.

“However, our data suggests that in stormy seas the bubble-induced asymmetry in dissolving into the oceans, as compared to previously dissolved carbon dioxide being released back into the atmosphere, is many times greater than scientists currently estimate.

“The excess Co2, which gas dissolves into stormy seas through bubbles, will increase as the proportion of CO2 in the atmosphere increases.

The study was published in collaboration between Professor Tim Leighton, his Ph.D. student Dr. David Coles, Professor Paul White at the University of Southampton’s Institute of Sound and Vibration Research, Professor Meric Srokosz from the National Oceanography Centre and Dr. David Woolf.

The research team have passed on all of their methods, equipment, computer codes and findings to other groups around the UK for further investigation.

Source: phys.org

(Dipla Aikaterini)

Another extreme heat wave strikes the North Pole

imrs.php

In four of the past five winters, the North Pole has witnessed dramatic temperatures spikes, which previously were rare. Now, in the lead up to summer, the temperature has again shot up to unusually high levels at the tip of the planet.

Scientists say this warming could hasten the melt of Arctic sea ice, which is already near record low levels.

In just the past few days, the temperature at the North Pole has soared to the melting point of 32 degrees, which is about 30-35 degrees (17-19 Celsius) above normal.

Much of the entire Arctic north of 80 degrees latitude is abnormally warm. The temperature averaged over the whole region appears to be the warmest on record for the time of year, dating back to at least 1958. It is about 18 degrees (10 Celsius) above the normal of 4 degrees (minus 16 Celsius).

As the warm air intruded the Arctic, sea ice melted suddenly. The Norway Ice Service tweeted the sea ice area near Svalbard, the small island chain between Norway and the North Pole, fell by about 32,000 square miles (82,000 square kilometers) to the second lowest area on record. The amount of ice lost is enough to cover the entire state of South Carolina.

Zachary Labe, a climate scientist at University of California in Irvine, said that such a pulse of warm, moist air into the Arctic can “have a long-lasting fingerprint” that preconditions the ice to melt more rapidly in the summer.

Indeed, a study published last year in the Journal of Geophysical Research found that these spring intrusions of warm, moist air can “can initiate sea ice melt that extends to a large area” through the summer and fall.

Already, Arctic sea ice is near its lowest extent on record. The Bering and Chukchi seas have never had so little ice in recorded history.

Interestingly, while much of the Arctic has turned abnormally warm, the cold air normally entrenched over the region has had to move somewhere. In recent days, it has parked over south central Greenland where temperatures are 30 to 35 degrees colder than normal.

Jesper Eriksen, a meteorologist with the Danish Meteorological Institute, tweeted that the temperature at Summit Station, near the top of the Greenland ice sheet, plummeted to minus 47 degrees (minus 44 Celsius), very close to the coldest temperature on record for the month of May of minus 50 (minus 45.6 Celsius).

The contrast between frigid air over interior Greenland and unusually mild air over the Arctic is leading to very stormy conditions over the Canadian Arctic Archipelago.

The warming of the Arctic and loss of ice are likely strongly connected to the buildup of greenhouse gases in the atmosphere from human activities. On Friday, a NOAA study was published that found that the “extraordinary heat” that affected the Arctic in 2016 “could not have happened without the steep increases in greenhouse gas concentrations.”

Source: washingtonpost.com

(Dipla Aikaterini)