Extreme weather triggered by global warming decides distribution of bugs, study shows

As global warming is advancing, the temperature in our planet increases. Many of the essential for the big number of creatures which are cold-blooded (ectothermic), including bugs. Their body's temperature is ultimately based on the ambient temperature, and also the same therefore is applicable towards the efficiency and speed of the vital biological processes.

But could it be alterations in climate or frequency of utmost temperature problems that possess the finest effect on species distribution? It was the questions that several Danish and Australian scientists made the decision to look at in many insect species.

Johannes Overgaard, Department of Bioscience, Aarhus College, Denmark, Michael R. Kearney and Ary A. Hoffmann, Melbourne College, Australia, lately released the outcomes of those studies within the journal Global Change Biology. The outcomes demonstrate that it's particularly the extreme temperature occasions that comprise the distribution of both tropical and temperate species. Thus global warming affects ectotermic creatures mainly because more periods of utmost weather are required later on.

Fruit flies were patterned

The scientists examined 10 fruit fly types of the genus Drosophila modified to tropical and temperate parts of Australia. First they examined the temps that the species can sustain growth and reproduction, and they found the limitations of tolerance for cold and hot temps.

"This is actually the very first time ever where we've been in a position to compare the results of extremes and alterations in average conditions inside a rigorous manner across several species," mentions Ary Hoffmann.

According to this understanding and understanding from the present distribution from the 10 species then they examined if distribution was correlated towards the temps needed for growth and reproduction in other words restricted to their ability to tolerate extreme temperature conditions.

"The solution was unambiguous: it's the species' ability to tolerate very hot or cold days that comprise their present distribution," states Johannes Overgaard.

Therefore, it is the ultimate weather occasions, for example prolonged high temperatures or very cold weather, that amounted to the bugs their existence, not a rise in climate.

Drastic changes available

With this particular information in hands, the scientists could then model how distributions are required to alter if global warming continues for the following a century.

Most terrestrial creatures experience temperature variation on daily and periodic time scale, and they're modified to those conditions. Thus, for any species to keep its existence under different temperature conditions you will find two simple conditions that must definitely be met. First of all, the temperature should from time to time be so that the species can grow and reproduce, and next, the temperature must not be so extreme the population's survival is threatened.

In temperate climate for instance, you will find many species that are modified to pass through low temps during the cold months, after which grow and reproduce within the summer time. In warmer environments, the task might be quite contrary. Here, the species might endure high temps throughout the dry hot summer time, while growth and reproduction mainly happens throughout the mild and wet winter period.

The end result was discouraging for those 10 species.

"Global warming can lead to less cold days or weeks, and therefore allow species to maneuver toward greater latitudes. However global warming also results in a greater incidence to very hot days and our model therefore forecasts the distribution of those species will disappear to under half their present distribution"states Johannes Overgaard.

"Actually, our forecasts are that some species would disappear entirely within the next couple of decades, even whether they have a reasonably wide distribution that presently covers 100s of kilometers," adds Ary Hoffmann.

"Although no 10 species analyzed are usually regarded as either dangerous or advantageous microorganisms for human society, the outcomes indicate that distribution of numerous insect species is going to be transformed significantly, and it'll most likely also affect most of the species which have particular social or commercial importance ," finishes Johannes Overgaard.

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Solar activity not a key cause of climate change, study shows

Climate change has not been strongly influenced by variations in heat from the sun, a new scientific study shows.

The findings overturn a widely held scientific view that lengthy periods of warm and cold weather in the past might have been caused by periodic fluctuations in solar activity.

Research examining the causes of climate change in the northern hemisphere over the past 1000 years has shown that until the year 1800, the key driver of periodic changes in climate was volcanic eruptions. These tend to prevent sunlight reaching Earth, causing cool, drier weather. Since 1900, greenhouse gases have been the primary cause of climate change.

The findings show that periods of low sun activity should not be expected to have a large impact on temperatures on Earth, and are expected to improve scientists' understanding and help climate forecasting.

Scientists at the University of Edinburgh carried out the study using records of past temperatures constructed with data from tree rings and other historical sources. They compared this data record with computer-based models of past climate, featuring both significant and minor changes in the sun.

They found that their model of weak changes in the sun gave the best correlation with temperature records, indicating that solar activity has had a minimal impact on temperature in the past millennium.

The study, published in Nature GeoScience, was supported by the Natural Environment Research Council.

Dr Andrew Schurer, of the University of Edinburgh's School of GeoSciences, said: "Until now, the influence of the sun on past climate has been poorly understood. We hope that our new discoveries will help improve our understanding of how temperatures have changed over the past few centuries, and improve predictions for how they might develop in future. Links between the sun and anomalously cold winters in the UK are still being explored."

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Study shows deeper meltdown at Japan nuke reactor (AP)

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Paper shows Japan feared aftershocks at nuke plant (AP)

TOKYO – Japan feared three months after the Fukushima nuclear power plant was hit by a tsunami that aftershocks could further damage one of its fuel storage pools, causing rods inside to melt and spew radiation within hours, according to a newly released document.

The Japan Nuclear Energy Safety Organization said it carried out a simulation that showed some 1,500 mostly used fuel rods at the plant's No. 4 reactor building could start breaking in two hours if aftershocks further damaged the pool and caused cooling water to escape. The fuel rods could start melting within eight hours, the organization said in a report dated June 30 and published Friday.

The report shows that the pool remained vulnerable for nearly four months until its operator completed reinforcement work in July. Tokyo Electric Power Co. had said before then that the building could withstand major aftershocks without reinforcement, but made repairs after acknowledging structural damage and water leaks from the pool area.

The March 11 quake and tsunami triggered meltdowns at the plant's three reactors. Explosions also damaged their buildings, plus Unit 4 next to them.

The simulation was based on a scenario that cooling water was lost in the Unit 4 spent fuel storage pool, located on the top floor of the building. The Unit 4 pool was considered high risk as it contained more fuel than the other three pools, as it also stored fuel rods that had been moved from the unit's reactor core, which was being fitted with new parts.

In the report, the government-funded JNES said a loss of pool water due to additional cracks from aftershocks could cause the fuel rods to overheat. Their casings could break and start spewing radiation in about 2 hours. Fuel pellets inside each rod could start melting within 7.7 hours at about 2,800 Celsius (5,000 Fahrenheit), it said.

The report was part of hundreds of pages of documents containing simulation results on dozens of accident scenarios by JNES earlier in the crisis.

Plant workers are still struggling to contain radiation still leaking from the plant, although the amount is far less than before.

TEPCO said Friday that Unit 1 — one of the most damaged buildings — now has an outer shell made of airtight polyester designed to contain radioactive particles inside the building. Similar covers are also planned for other buildings.

Government officials are also making massive decontamination efforts in areas around the plant, from where tens of thousands of people had to evacuate.

Recent discoveries of radiation "hot spots" in and around Tokyo have also caused fears among people there, where many concerned parents routinely check their neighborhoods for radiation. In most cases the reading is estimated to be below the internationally accepted annual limit, but critics say the standard exceeds Japan's cap before the accident and the government should expand the scope of decontamination.

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U.N. nuclear report shows Japan safety shortcomings (Reuters)

VIENNA (Reuters) – Japanese nuclear regulators failed to review and approve steps taken after 2002 to protect against tsunamis at the Fukushima plant and these proved insufficient to prevent the tidal wave disaster three months ago, a U.N. report showed.

A detailed assessment by experts from the International Atomic Energy Agency -- the first outside review of Japan's nuclear crisis -- suggested several shortcomings both before and after a tidal wave crippled the power station three months ago.

But it also praised the way workers on the ground dealt with the situation at Fukushima Daiichi after the massive earthquake and huge tsunami devastated its reactors on March 11, triggering the world's worst nuclear catastrophe in a quarter of a century.

Given the extreme circumstances it is doubtful "that any better solutions than the ones actually chosen could have been realistically implemented," said the 160-page report, prepared for a ministerial nuclear safety meeting in Vienna next week.

A three-page summary was issued at the end of the 18-member team's May 24-June 2 inspector mission to Japan. It said the country underestimated the threat from tsunamis to the Fukushima plant and urged sweeping changes to its regulatory system.

Japanese authorities have been criticized for failing to plan for a tsunami that would surge over the 5.7 meter (19-ft) wall at the nuclear power station in the country's northeast, despite warnings that such a risk was looming.

The wave that crashed into the complex after the 9.0 magnitude earthquake was about 14 meters (46 feet) high.

In another setback to efforts to restore control over the quake-stricken plant, a rise in radiation halted the clean-up of radioactive water at Fukushima on Saturday only hours after it got under way.

The full IAEA report said there had been "insufficient defense-in-depth provisions" for tsunami hazards, even though they had been considered in the design and siting of the plant operated by Tokyo Electric Power Company, or Tepco.

DECISION DELAYS

Extra protective steps were taken as a result of an evaluation after 2002 -- the projected tsunami height was increased -- but they were insufficient "to cope with the high tsunami run-up values and all associated hazardous phenomena."

"Moreover, those additional protective measures were not reviewed and approved by the regulatory authority," said the report. It added: "Severe accident management provisions were not adequate to cope with multiple plant failures."

The document, obtained by Reuters, was submitted to IAEA member states on Friday but has not yet been made public.

At the June 20-24 IAEA-hosted meeting, some 150 nations will begin charting a strategy on boosting global nuclear safety, but differences on how much international action is needed may hamper follow-up efforts, diplomats say.

Japan's crisis has prompted a rethink of energy policy around the world, underlined by Germany's decision to shut down all its reactors by 2022 and an Italian vote to ban nuclear power for decades.

Three reactors at the Japanese complex went into meltdown when power and cooling functions failed, causing radiation leakage and forcing the evacuation of some 80,000 people.

Japanese officials have come under fire for their handling of the emergency and the authorities have admitted that lax standards and poor oversight contributed to the accident.

In 2007, the IAEA was ignored when it called on Japan to create a more powerful and independent nuclear regulator, and the report underlined the need for greater regulatory control.

"An updating of regulatory requirements and guidelines should be performed reflecting the experience and data obtained during the Great East Japan Earthquake and Tsunami," it said.

Japan has a well organized emergency preparedness and response system but "complicated structures and organizations can result in delays in urgent decision making," it added.

The report also listed wider lessons for improving nuclear safety worldwide and help avert any repeat of the disaster, saying reactors should be built so that they can withstand rare and "complex combinations" of external threats.

(Editing by Mark Heinrich)

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