High temps due to global warming will be dramatic even for tardigrades

Global warming, a major aspect of climate change, is already causing a wide range of negative impacts on many habitats of our planet. It is thus of the utmost importance to understand how rising temperatures may affect animal health and welfare. A research group from Department of Biology, University of Copenhagen has just shown that tardigrades are very vulnerable to long-term high temperature exposures. Animals, which in their desiccated state are best known for their extraordinary tolerance to extreme environments.

In a study published recently in Scientific Reports, Ricardo Neves and Nadja Møbjerg and colleagues at Department of Biology, University of Copenhagen present results on the tolerance to high temperatures of a tardigrade species.

Tardigrades, commonly known as water bears or moss piglets, are microscopic invertebrates distributed worldwide in marine, freshwater and terrestrial microhabitats.

Ricardo Neves, Nadja Møbjerg and colleagues investigated the tolerance to high temperatures of Ramazzottius varieornatus, a tardigrade frequently found in transient freshwater habitats.

- "The specimens used in this study were obtained from roof gutters of a house located in Nivå, Denmark. We evaluated the effect of exposures to high temperature in active and desiccated tardigrades, and we also investigated the effect of a brief acclimation period on active animals," explains postdoc Ricardo Neves.

Rather surprisingly the researchers estimated that for non-acclimated active tardigrades the median lethal temperature is 37.1°C, though a short acclimation periods leads to a small but significant increase of the median lethal temperature to 37.6°C. Interestingly, this temperature is not far from the currently measured maximum temperature in Denmark, i.e. 36.4°C. As for the desiccated specimens, the authors observed that the estimated 50% mortality temperature is 82.7°C following 1 hour exposures, though a significant decrease to 63.1°C following 24 hour exposures was registered.

The research group used logistic models to estimate the median lethal temperature (at which 50% mortality is achieved) both for active and desiccated tardigrades.

Approximately 1300 tardigrade species have been described so far. The body of these minute animals is barrel-shaped (or dorsoventrally compressed) and divided into a head and a trunk with four pairs of legs. Their body length varies between 50 micrometers and 1.2 millimeters. Apart from their impressive ability to tolerate extreme environments, tardigrades are also very interesting because of their close evolutionary relationship with arthropods (e.g., insects, crustaceans, spiders).

As aquatic animals, tardigrades need to be surrounded in a film of water to be in their active state (i.e., feeding and reproducing). However, these critters are able to endure periods of desiccation (anhydrobiosis) by entering cryptobiosis, i.e., a reversible ametabolic state common especially among limno-terrestrial species. Succinctly, tardigrades enter the so-called "tun" state by contracting their anterior-posterior body axis, retracting their legs and rearranging the internal organs. This provides them with the capacity to tolerate severe environmental conditions including oxygen depletion (anoxybiosis), high toxicant concentrations (chemobiosis), high solute concentration (osmobiosis) and extremely low temperatures (cryobiosis).

The extraordinary tolerance of tardigrades to extreme environments includes also high temperature endurance. Some tardigrade species were reported to tolerate temperatures as high as 151°C. However, the exposure time was only of 30 minutes. Other studies on thermotolerance of desiccated (anhydrobiotic) tardigrades revealed that exposures higher than 80°C for 1 hour resulted in high mortality, with almost all specimens dying at temperatures above 103°C. It remained, yet, unknown how anhydrobiotic tardigrades handle exposures to high temperatures for long periods, i.e., exceeding 1 hour.

- "From this study, we can conclude that active tardigrades are vulnerable to high temperatures, though it seems that these critters would be able to acclimatize to increasing temperatures in their natural habitat. Desiccated tardigrades are much more resilient and can endure temperatures much higher than those endured by active tardigrades. However, exposure-time is clearly a limiting factor that constrains their tolerance to high temperatures.," says Ricardo Neves.

Indeed, although tardigrades are able to tolerate a diverse set of severe environmental conditions, their endurance to high temperatures is noticeably limited and this might actually be the Achilles heel of these otherwise super-resistant animals.


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Materials provided by Faculty of Science - University of Copenhagen. Note: Content may be edited for style and length.

Global warming trend will continue in 2020

London, Dec 20 (Prensa Latina) The trend of rising temperatures will continue next year with an average of 1.11 degrees Celsius in relation to pre-industrial levels, according to data reported by Met Office, a UK meteorological service.

2020 will be added to the series of the hottest years in history for six consecutive years and its main cause is the increase in greenhouse gas emissions, explains the entity in its report.

In addition, the text remembers that the warmest year so far was 2016, when a strong El Niño phenomenon made a significant difference.

This meteorological phenomenon causes sea surface temperatures to increase in the central and eastern Pacific and is associated with a series of impacts worldwide, including the overall level of global warming, it explains.

However, the chances of a strong El Niño in 2020 are low, the source specifies.

It details that the global average temperature next year will be in the range of 0.99 to 1.23 degrees Celsius with a central estimate of 1.11.

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Planet SOS: Transforming the way we use land and its resources

We rely on land for our food and to meet many of our basic needs. But the UN's Intergovernmental Panel on Climate Change (IPCC) says poor land-use practices are causing land degradation and desertification.

The land is losing its ability to sustain life.

Planet SOS talks to some of those trying to protect the Earth's green bastions.

Al Jazeera's David Mercer meets the Guatemalan villagers using the global system of land concessions to both use and protect their forest.

Emma Hayward travels to Wales where some farmers are employing sustainable practices to reduce the impact of pastoral farming.

We speak to environmental activist George Monbiot on ways of overhauling the global food system.

Nicolas Haque returns to Senegal to assess progress on the Great Green Wall, a project to restore land from east, right across to west Africa by planting trees.

Mohamed Vall explores possible solutions that could get people back to land they once abandoned when the water stopped flowing.

Planet SOS conducts a taste-test on the plant-based burger products that some are calling the future of food.

And Mereana Hond looks ahead to COP25, the climate talks taking place this year in Madrid.

Climate change: Greenhouse gas concentrations again break records

Atmospheric concentrations of carbon dioxide and other greenhouse gases once again reached new highs in 2018.

The World Meteorological Organization (WMO) says the increase in CO2 was just above the average rise recorded over the last decade.

Levels of other warming gases, such as methane and nitrous oxide, have also surged by above average amounts.

Since 1990 there's been an increase of 43% in the warming effect on the climate of long lived greenhouse gases.

The WMO report looks at concentrations of warming gases in the atmosphere rather than just emissions.

The difference between the two is that emissions refer to the amount of gases that go up into the atmosphere from the use of fossil fuels, such as burning coal for electricity and from deforestation.

Concentrations are what's left in the air after a complex series of interactions between the atmosphere, the oceans, the forests and the land. About a quarter of all carbon emissions are absorbed by the seas, and a similar amount by land and trees.

Using data from monitoring stations in the Arctic and all over the world, researchers say that in 2018 concentrations of CO2 reached 407.8 parts per million (ppm), up from 405.5ppm a year previously.

This increase was above the average for the last 10 years and is 147% of the "pre-industrial" level in 1750.

The WMO also records concentrations of other warming gases, including methane and nitrous oxide. About 40% of the methane emitted into the air comes from natural sources, such as wetlands, with 60% from human activities, including cattle farming, rice cultivation and landfill dumps.

Methane is now at 259% of the pre-industrial level and the increase seen over the past year was higher than both the previous annual rate and the average over the past 10 years.

Nitrous oxide is emitted from natural and human sources, including from the oceans and from fertiliser-use in farming. According to the WMO, it is now at 123% of the levels that existed in 1750.

Last year's increase in concentrations of the gas, which can also harm the ozone layer, was bigger than the previous 12 months and higher than the average of the past decade.

What concerns scientists is the overall warming impact of all these increasing concentrations. Known as total radiative forcing, this effect has increased by 43% since 1990, and is not showing any indication of stopping.

deforestation

"There is no sign of a slowdown, let alone a decline, in greenhouse gases concentration in the atmosphere despite all the commitments under the Paris agreement on climate change," said WMO Secretary-General Petteri Taalas.

"We need to translate the commitments into action and increase the level of ambition for the sake of the future welfare of mankind," he added.

"It is worth recalling that the last time the Earth experienced a comparable concentration of CO2 was three to five million years ago. Back then, the temperature was 2-3C warmer, sea level was 10-20m higher than now," said Mr Taalas.

The UN Environment Programme will report shortly on the gap between what actions countries are taking to cut carbon and what needs to be done to keep under the temperature targets agreed in the Paris climate pact.

Preliminary findings from this study, published during the UN Secretary General's special climate summit last September, indicated that emissions continued to rise during 2018.

Both reports will help inform delegates from almost 200 countries who will meet in Madrid next week for COP25, the annual round of international climate talks.

 

Fears for endangered orcas as marine heatwave hits northeast Pacific

An ocean heatwave has hit the west coast of North America, threatening to disrupt marine life including salmon, sea lions and endangered orcas.

A marine heatwave is defined as at least five days where seawater temperatures are “extremely high” for the location.

The expanse of unusually warm water in the northeast Pacific Ocean stretches from Alaska to California, researchers with the National Oceanic and Atmospheric Administration said.

It resembles a similar heat wave about five years ago that was blamed for poorer survival rates for young salmon, more humpback whales becoming entangled in fishing gear as they hunted closer to shore, and an algae bloom that shut down crabbing and clamming operations.

“Given the magnitude of what we saw last time, we want to know if this evolves on a similar path,” said Chris Harvey, a research scientist at the Northwest Fisheries Science Center.

NOAA Fisheries said the water has reached temperatures more than 5° Fahrenheit (2.8° Celcius) above average. It remains to be seen whether this heat wave dissipates more quickly than the last one, which occurred in 2014, the agency said.

If it lingers, it could be disastrous for the Pacific Northwest’s endangered orcas, which largely depend on chinook salmon.

Warmer waters can weaken the food web that sustain the salmon and bring predators of young salmon, including seabirds, closer to shore, further reducing their abundance.

Chinook returns have been extremely low in recent years following the last heat wave, which scientists dubbed “the blob.”

The new heat wave has emerged over the last few months, growing in a similar pattern in the same area. After “the blob,” it’s the second-most widespread heat wave in the northern Pacific Ocean in the last 40 years — as far back as the relevant data goes.

“It’s on a trajectory to be as strong as the prior event,” said Andrew Leising, a research scientist at NOAA Fisheries’ Southwest Fisheries Science Center in La Jolla, California, who developed a way to use satellite data to track marine heat waves in the Pacific.

Among the causes is a persistent low-pressure weather pattern between Hawaii and Alaska that has weakened winds that otherwise might mix and cool surface waters across much of the North Pacific, said Nathan Mantua, a NOAA research scientist.

The last marine heatwave to hit the region was in 2014. NOAA
The last marine heatwave to hit the region was in 2014. NOAA

What’s causing that, he said, is unclear: It might simply reflect the normal chaotic motion of the atmosphere, or it might be related to the warming of the oceans and other effects of human-made climate change.

The agency said it will provide fisheries managers with information on how the unusually warm conditions could affect the marine ecosystem and fish stocks.

The last heat wave spanned 2014 and 2015 and resulted in several declared fisheries disasters.

Among the other effects, thousands of young sea lions were stranded on beaches after their mothers were forced to forage further from their rookeries in the Channel Islands off Southern California.

In March, scientists revealed an alarming increase in the frequency of marine heatwaves. The first global analysis to measure the impact of temperature spikes in the ocean found that they had already damaged ecosystems across the world and were likely to become even more destructive, with “devastating consequences for human health, economies and the environment”.

The number of marine heatwave days has increased by more than 50 per cent since the mid-20th century.

Europe warming faster than expected due to climate change

Climate change is increasing the number of days of extreme heat and decreasing the number of days of extreme cold in Europe, posing a risk for residents in the coming decades, according to a new study.

Temperatures in Europe have hit record highs this summer, passing 46.0 degrees Celsius (114.8 degrees Fahrenheit) in southern France. New research in the AGU journal Geophysical Research Letters finds the number of summer days with extreme heat has tripled since 1950 and summers have become hotter overall, while the number of winter days with extreme cold decreased in frequency by at least half and winters have become warmer overall.

The new study finds parts of Europe are warming faster than climate models project.

"Even at this regional scale over Europe, we can see that these trends are much larger than what we would expect from natural variability. That's really a signal from climate change," said Ruth Lorenz, a climate scientist at the Swiss Federal Institute of Technology in Zurich, Switzerland, and lead author of the new study.

Extreme heat is dangerous because it stresses the human body, potentially leading to heat exhaustion or heat stroke. Scientists knew climate change was warming Europe, but they mostly studied long-term changes in extreme temperatures. The new study looked at observational data to evaluate whether the climate models used for regional projections can reproduce observed trends.

In the new study, Lorenz and her colleagues used observational data taken by European weather stations from 1950-2018 and then analyzed the top 1% of the hottest heat extremes and highest humidity extremes, and the top 1% coldest days during that period.

"We looked further at the hottest day or coldest night per year, so for each year we looked for the maximum/minimum value and how these changed over time," Lorenz said.

They found the number of extreme heat days in Europe has tripled since 1950, while the number of extreme cold days decreased by factors of two or three depending on the region. Extremely hot days have become hotter by an average of 2.30 degrees Celsius (4.14 degrees Fahrenheit), while extremely cold days have warmed by 3.0 degrees Celsius (5.4 degrees Fahrenheit) on average. The hottest days and coldest nights warmed significantly more than their corresponding summer and winter mean temperatures.

Individual regions throughout Europe experienced drastically different temperature trends, which makes it difficult to compare the average European temperatures to specific stations' extremes, according to the authors. In Central Europe, the extremes warmed by 0.14 degrees Celsius (0.25 degrees Fahrenheit) per decade more than the summer mean, equivalent to an almost 1.0 degree Celsius (1.8 degree Fahrenheit) increase more than the average over the whole study period, according to Lorenz.

More than 90% of the weather stations studied showed the climate was warming, a percentage too high to purely be from natural climate variability, according to the researchers.

The results also showed that the region was warming faster than climate models projected. Some regions experienced higher extremes than expected and some had lower extremes that expected.

"In the Netherlands, Belgium, France, the model trends are about two times lower than the observed trends," said Geert Jan van Oldenborgh, a climate analysist at the Royal Netherlands Meteorological Institute in De Bilt, Netherlands, who was not connected to the new study. "We're reaching new records faster than you'd expect."

European summers and winters will only grow hotter in the coming years as climate change accelerates, impacting cities and people unprepared for rising temperatures, according to the study authors.

"Lots of people don't have air conditioning for instance and it makes this really important," Lorenz said. "We expected results based on modeling studies but it's the first time we see it in what we've observed so far."

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Materials provided by American Geophysical Union. Note: Content may be edited for style and length.


Experts climate change in Havana

Havana, July 3 (RHC)—The 12th International Convention on Environment and Development is underway in Havana with the attendance of experts coming from some 50 countries. The gathering is convened by the Environment Agency of the Ministry of Science,Technology and Environment of the Republic of Cuba,

On  Wednesday, the event is focusing on the commitment made for this decade by Latin America and the Caribbean for the attention of protected areas.

Delegates will also discuss environmental degradation, drought, deforestation, the use of unfriendly practices to the environment and the huge amount of plastic products that end up in the sea, with great impact on many marine species.

“For integration and Cooperation” is the Convention´s theme, which includes six congresses: Management of biodiversity; Environmental management and protected areas. Environmental education, politics and law as well as climate change.

Experts on this subjects will discuss their views on how human actions are triggering climate change and the increase of extreme weather events.

Edited by Jorge Ruiz Miyares

Continental Europe braced for 'potentially dangerous' heatwave

High pressure pulling hot air northward from Africa will send temperatures soaring

A potentially record-breaking heatwave is forecast to grip much of continental Europe next week, with temperatures in cities from Spain to Germany expected to exceed 32C and climb to more than 38C or even 40C in the hottest areas.

The combination of a storm stalled over the Atlantic and high pressure over central Europe would pull very hot air from Africa northward, leading to a “potentially dangerous heatwave over a large portion of western and central Europe”, forecaster AccuWeather said.

In France, temperatures of between 35C and 40C were expected across most of the country except Brittany from Monday, Météo-France said, and were unlikely to fall below 20C overnight.

“Even though it will be shortlived, this heatwave could be remarkable for its momentum and intensity,” the forecaster said in a bulletin.

France’s health minister, Agnès Buzyn, warned local authorities, hospitals and retirement homes to be on high alert, noting that last summer’s heatwave resulted in 1,500 more deaths than normal in July and August.

Meteorologists in Germany said there was a 50% chance of temperatures hitting 40C, possibly breaking the national record of 40.3C set in Bavaria in 2015.

AccuWeather said cities from Madrid to Berlin, including Paris, Brussels and Frankfurt, were likely to experience a “multi-day heatwave” in the first half of the week, with similar temperatures of 32C or above expected further east later in Bucharest, Vienna, Budapest, Belgrade and Sofia.

“Multiple days of extreme heat combined with warm nights will not allow buildings and homes without air conditioning to cool off, creating uncomfortable sleeping conditions and also raising the risk of heat-related illnesses,” the forecaster’s senior meteorologist, Eric Leister, said.

“The elderly and children are most at risk from such ailments, and outdoor exposure should be limited during the hottest times of the day to reduce the risk of illness.”

Long-range weather forecasts show summer temperatures throughout July and August are expected to be higher than normal, rivalling those of 2018, which according to the European Environment Agency was one of the three warmest years on record on the continent.

Scientists have said last year’s heatwave, which led to increased mortality rates, a dramatic decline in crop yields, the shutdown of nuclear power plants and wildfires inside the Arctic Circle, was linked to the climate emergency and that extreme climate events are likely to be regular occurrences in the coming decades.

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