Reduced energy from the sun might occur by mid-century: Now scientists know by how much

The Sun might emit less radiation by mid-century, giving planet Earth a chance to warm a bit more slowly but not halt the trend of human-induced climate change.

The cooldown would be the result of what scientists call a grand minimum, a periodic event during which the Sun's magnetism diminishes, sunspots form infrequently, and less ultraviolet radiation makes it to the surface of the planet. Scientists believe that the event is triggered at irregular intervals by random fluctuations related to the Sun's magnetic field.

Scientists have used reconstructions based on geological and historical data to attribute a cold period in Europe in the mid-17th Century to such an event, named the "Maunder Minimum." Temperatures were low enough to freeze the Thames River on a regular basis and freeze the Baltic Sea to such an extent that a Swedish army was able to invade Denmark in 1658 on foot by marching across the sea ice.

A team of scientists led by research physicist Dan Lubin at Scripps Institution of Oceanography at the University of California San Diego has created for the first time an estimate of how much dimmer the Sun should be when the next minimum takes place.

There is a well-known 11-year cycle in which the Sun's ultraviolet radiation peaks and declines as a result of sunspot activity. During a grand minimum, Lubin estimates that ultraviolet radiation diminishes an additional seven percent beyond the lowest point of that cycle. His team's study, "Ultraviolet Flux Decrease Under a Grand Minimum from IUE Short-wavelength Observation of Solar Analogs," appears in the publication Astrophysical Journal Letters and was funded by the state of California.

"Now we have a benchmark from which we can perform better climate model simulations," Lubin said. "We can therefore have a better idea of how changes in solar UV radiation affect climate change."

Lubin and colleagues David Tytler and Carl Melis of UC San Diego's Center for Astrophysics and Space Sciences arrived at their estimate of a grand minimum's intensity by reviewing nearly 20 years of data gathered by the International Ultraviolet Explorer satellite mission. They compared radiation from stars that are analogous to the Sun and identified those that were experiencing minima.

The reduced energy from the Sun sets into motion a sequence of events on Earth beginning with a thinning of the stratospheric ozone layer. That thinning in turn changes the temperature structure of the stratosphere, which then changes the dynamics of the lower atmosphere, especially wind and weather patterns. The cooling is not uniform. While areas of Europe chilled during the Maunder Minimum, other areas such as Alaska and southern Greenland warmed correspondingly.

Lubin and other scientists predict a significant probability of a near-future grand minimum because the downward sunspot pattern in recent solar cycles resembles the run-ups to past grand minimum events.

Despite how much the Maunder Minimum might have affected Earth the last time, Lubin said that an upcoming event would not stop the current trend of planetary warming but might slow it somewhat. The cooling effect of a grand minimum is only a fraction of the warming effect caused by the increasing concentration of carbon dioxide in the atmosphere. After hundreds of thousands of years of CO2 levels never exceeding 300 parts per million in air, the concentration of the greenhouse gas is now over 400 parts per million, continuing a rise that began with the Industrial Revolution. Other researchers have used computer models to estimate what an event similar to a Maunder Minimum, if it were to occur in coming decades, might mean for our current climate, which is now rapidly warming.

One such study looked at the climate consequences of a future Maunder Minimum-type grand solar minimum, assuming a total solar irradiance reduced by 0.25 percent over a 50-year period from 2020 to 2070. The study found that after the initial decrease of solar radiation in 2020, globally averaged surface air temperature cooled by up to several tenths of a degree Celsius. By the end of the simulated grand solar minimum, however, the warming in the model with the simulated Maunder Minimum had nearly caught up to the reference simulation. Thus, a main conclusion of the study is that "a future grand solar minimum could slow down but not stop global warming."

Donald Trump is hampering fight against climate change, WEF warns

The World Economic Forum delivered a strong warning about Donald Trump’s go-it-alone approach to tackling climate change as it highlighted the growing threat of environmental collapse in its annual assessment of the risks facing the international community.

In the run-up to the US president’s speech to its annual meeting in Davos, Switzerland, next week, the WEF avoided mentioning Trump by name but said “nation-state unilateralism” would make it harder to tackle global warming and ecological damage.

The WEF’s global risks perception survey showed Trump’s arrival in the White House in 2017 had coincided with a marked increase in concern about the environment among experts polled by the Swiss-based organisation.

t said all five environmental risks covered by the survey – extreme weather events, natural disasters, failure of climate-change mitigation and adaptation, biodiversity loss and ecosystem collapse, and human-made natural disasters – had become more prominent.

“This follows a year characterised by high-impact hurricanes, extreme temperatures and the first rise in CO2 emissions for four years. We have been pushing our planet to the brink and the damage is becoming increasingly clear.

“Biodiversity is being lost at mass-extinction rates, agricultural systems are under strain, and pollution of the air and sea has become an increasingly pressing threat to human health.”

Trump has threatened to withdraw the US from the 2015 Paris agreement under which nations agreed to take steps to limit the increase in global temperature. He has said the commitments made by his predecessor, Barack Obama, would damage the American economy.

Other states have said they will keep to the pledges made in Paris, an approach supported by the WEF.

“A trend towards nation-state unilateralism may make it more difficult to sustain the long-term, multilateral responses that are required to counter global warming and the degradation of the global environment,” it said.

The survey said the extreme weather events in 2017 included unusually frequent Atlantic hurricanes, with September the most intense month on record. It was also the most expensive hurricane season.

It added that when data was finalised, 2017 would be among the three hottest years on record, and the hottest without an El Niño, the Pacific Ocean climate cycle that affects the world’s weather.

Biodiversity loss was occurring at mass-extinction rates, the WEF said, noting that the populations of vertebrate species declined by an estimated 58% between 1970 and 2012.

“Globally, the primary driver of biodiversity loss is the human destruction of habitats including forests – which are home to approximately 80% of the world’s land-based animals, plants and insects – for farming, mining, infrastructure development and oil and gas production.”

Stronger than expected growth in 2017 meant economic risks were seen as less pressing, but the WEF said the upbeat picture masked continuing underlying concerns, including unsustainable asset prices; high levels of indebtedness, particularly in China; and continuing strains in the global financial system.

The International Monetary Fund is likely to raise its forecast for global growth when it gives its latest economic update in Davos next Monday, and the WEF survey said the recovery underway in all major economies had to led to a sharp improvement in sentiment.

But it expressed concern that the swing to optimism might lead to complacency and a blind spot to economic risks. “There are certainly reasons to be cautious: one does not have to look far for signs of economic and financial strain”, the WEF added, calling for greater attention to be paid to the risks of another crisis erupting.

The survey warned there would be limited policy firepower in the event of a new crisis. It also warned of the disruption caused by automation, noting that “for the foreseeable future, automation and digitalisation can be expected to push down on levels of employment and wages, and contribute to increases in income and wealth at the top of the distribution.”

It also highlighted the buildup of protectionist pressures against a backdrop of rising nationalist and populist politics and growing cybersecurity risks.

The WEF said cyber attacks against businesses had almost doubled in five years, and that the financial impact of cybersecurity breaches was rising.

  • Published in World

Climate change could expose volcanic regions, increase eruptions: Study

Climate change caused by humans is rapidly melting ice in volcanically active regions, which could lead to increased volcano eruptions, a study has found.

Climate change caused by humans is rapidly melting ice in volcanically active regions, which could lead to increased volcano eruptions, a study has found. The study, led by researchers at the University of Leeds in the UK, found that there was less volcanic activity in Iceland when glacier cover was more extensive and as the glaciers melted volcanic eruptions increased due to subsequent changes in surface pressure.

“Climate change caused by humans is creating rapid ice melt in volcanically active regions. In Iceland, this has put us on a path to more frequent volcanic eruptions,” said Graeme Swindles from the School of Geography at Leeds. The study examined Icelandic volcanic ash preserved in peat deposits and lake sediments and identified a period of significantly reduced volcanic activity between 5,500 and 4,500 years ago.

This period came after a major decrease in global temperature, which caused glacier growth in Iceland. The findings, published in the journal Geology, found there was a time lag of roughly 600 years between the climate event and a noticeable decrease in the number of volcanic eruptions. The study suggests that perhaps a similar time lag can be expected following the more recent shift to warmer temperatures.

Icelandic volcanism is controlled by complex interactions between rifts in continental plate boundaries, underground gas and magma build-up and pressure on the volcano’s surface from glaciers and ice. (File Photo)

Iceland’s volcanic system is in process of recovering from the ‘Little Ice Age’ – a recorded period of colder climate roughly between the years 1500 and 1850 AD, researchers said. Since the end of the Little Ice Age, a combination of natural and human caused climate warming is causing Icelandic glaciers to melt again, they said. “The human effect on global warming makes it difficult to predict how long the time lag will be but the trends of the past show us more eruptions in Iceland can be expected in the future,” Swindles said.

“These long term consequences of human effect on the climate is why summits like COP are so important. It is vital to understand how actions today can impact future generations in ways that have not been fully realised, such as more ash clouds over Europe, more particles in the atmosphere and problems for aviation,” he said. Icelandic volcanism is controlled by complex interactions between rifts in continental plate boundaries, underground gas and magma build-up and pressure on the volcano’s surface from glaciers and ice.

Changes in surface pressure can alter the stress on shallow chambers where magma builds up. “When glaciers retreat there is less pressure on the Earth’s surface. This can increase the amount of mantle melt as well as affect magma flow and how much magma the crust can hold,” said Ivan Savov, from the School of Earth & Environment at Leeds. “Even small changes in surface pressure can alter the likelihood of eruptions at ice-covered volcanos,” said Savov.

 

Climate change may be vastly underestimated due to ocean temperature miscalculations - study

Scientists have discovered a flaw in the method used to measure past ocean temperatures which, if correct, could mean we have underestimated the rate of climate change over the past 100 million years.

According to the current methodology, the temperature of the ocean depths, and the surface of the polar ocean, was some 15C (59F) higher 100 million years ago, compared to now.

These estimates have been challenged, however, by a joint team of researchers from the French National Center for Scientific Research (CNRS) and the Swiss Federal Institute of Technology in Lausanne (EPFL).

In their study, published in Nature Communications, the team posits that ocean temperatures may have remained relatively stable throughout this period, raising serious concerns about the current level of climate change being experienced by Mother Earth.

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“If we are right, our study challenges decades of paleoclimate research,” EPFL’s Anders Meibom said. “Oceans cover 70 percent of our planet. They play a key role in the Earth's climate. Knowing the extent to which their temperatures have varied over geological time is crucial if we are to gain a fuller understanding of how they behave and to predict the consequences of current climate change more accurately.”

Researchers believe that over the last 50 years certain processes used in current methodology were overlooked. Scientists have used foraminifera, which are tiny marine fossils found in the sediment cores extracted from the ocean floor, to calculate ocean temperatures.

This is done by calculating the levels of oxygen-18 content in the calcareous shells of foraminifera. The level of oxygen-18 is dependent on the temperature of the ocean in which the foraminifera live.

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The problem now, it seems, is that all of these estimates were based on the principle that the oxygen-18 content remained constant while the fossils were in the sediment. To test this theory, the team exposed the foraminifera to high temperatures in simulated seawater that only contained oxygen-18.

The results show that “the level of oxygen-18 present in the foraminifera tests can in fact change without leaving a visible trace, thereby challenging the reliability of their use as a thermometer.”

“What appeared to be perfectly preserved fossils are in fact not,” CNRS researcher Sylvain Bernard said. This basically means that previous estimates of ocean temperatures are simply incorrect and instead of showing the aforementioned 15C-degree drop over the last 100 million years, the study notes that “these measurements simply reflect the change in oxygen-18 content in the fossil foraminifera tests.”

“This change appears to be the result of a process called re-equilibration: during sedimentation, temperatures rise by 20 to 30C, causing the foraminifera tests to re-equilibrate with the surrounding water,” the study says.

But what next? Well, Meibom says scientists will now have to revisit the ocean's paleotemperatures and “carefully quantify this re-equilibration, which has been overlooked for too long.”

The researchers say that they will now focus on a number of other marine organisms to see if they can “clearly understand what took place in the sediment over geological time.”

 

Climate change may force planes to lighten loads or stay grounded – study

The effects of climate change may extend further than melting glaciers and rising sea levels, according to a new study which says that hot temperatures may cause up to 30 percent of airplanes to be grounded in coming decades.

The study, published in the journal Climatic Change on Thursday, says that 10 to 30 percent of fully loaded airplanes may at some point be forced to adapt during the hottest part of the day. 

Those adaptations include removing fuel, cargo, or passengers, or waiting for cooler hours to fly.

 
Physicist Stephen Hawking and U.S. President Donald Trump © Reuters

The potential take-off problems would be due to the fact that as air warms, it spreads out and its density declines.

“In thinner air, wings generate less lift as a plane races along the runway. Thus, depending on the aircraft model, runway length, and other factors, at some point a packed plane may be unable to take off safely if the temperature gets too high,” Columbia University, whose researchers took part in the study, wrote in a press release. 

“Weight must be dumped, or else the flight delayed or canceled,” it continues.

The study’s authors estimate that fuel capacities and payload weights would have to be reduced as much as four percent for some aircraft.

To put those numbers in perspective, an average 160-seat aircraft would need roughly 12 or 13 less passengers to reach a four-percent weight reduction.

However, if carbon emissions were to somehow be sharply reduced in the near future, those reductions could amount to as little as 0.5 percent.

Planes with lower temperature tolerances would struggle more, according to the study. Airports which have shorter runways, or which are located in hotter parts of the world or in higher elevations will also suffer more than others.

 
© NERC / National Oceanography Centre

Airports which would be in danger in those cases include New York’s LaGuardia, which has short runways. Dubai International Airport in the United Arab Emirates would suffer due to its very high temperatures.

“Airports probably less affected because they are in temperate regions and have long runways include New York’s JFK, London Heathrow and Paris’s Charles de Gaulle,” the Columbia press release states.

In theory, the potential problems could be somewhat mitigated with new engine or body designs for aircraft, or expanded runways, according to study co-author Radley Horton, a climatologist at Columbia University’s Lamont-Doherty Earth Observatory.

However, such solutions are unlikely to be implemented, as planes are already highly engineered for efficiency, and there simply isn’t room to expand runways in major cities such as New York.

“The sooner climate can be incorporated into mid- and long-range plans, the more effective adaptation efforts can be,” said co-author Ethan Coffel, a Columbia University PhD student.

  • Published in World

Vulnerable ‘chokepoints’ threaten global food supply, warns report

Fourteen critical bottlenecks, from roads to ports to shipping lanes, are increasingly at risk from climate change, say analysts.

Increasingly vulnerable “chokepoints” are threatening the security of the global food supply, according to a new report. It identifies 14 critical locations, including the Suez canal, Black Sea ports and Brazil’s road network, almost all of which are already hit by frequent disruptions.

With climate change bringing more incidents of extreme weather, analysts at the Chatham House thinktank warn that the risk of a major disruption is growing but that little is being done to tackle the problem. Food supply interruptions in the past have caused huge spikes in prices which can spark major conflicts.

The chokepoints identified are locations through which exceptional amounts of the global food trade pass. More than half of the globe’s staple crop exports – wheat, maize, rice and soybean – have to travel along inland routes to a small number of key ports in the US, Brazil and the Black Sea. On top of this, more than half of these crops – and more than half of fertilisers – transit through at least one of the maritime chokepoints identified.

“We are talking about a huge share of global supply that could be delayed or stopped for a significant period of time,” said Laura Wellesley, one of the authors of the Chatham House report. “What is concerning is that, with climate change, we are very likely to see one or more of these chokepoint disruptions coincide with a harvest failure, and that’s when things start to get serious.”

The chokepoints are already suffering repeated disruptions, the report found. US inland waterways and railways, which carry 30% of the world’s maize and soy, were hit by flooding that halted traffic in 2016 and a 2012 heatwave that kinked rail lines and caused derailments.

The Panama canal has been hampered by drought, while the Suez canal has been closed by sandstorms and threatened by attempted terrorist bomb attacks. Brazil’s muddy roads are often closed by heavy rain, with 3,000 trucks stranded earlier in 2017, while its vital southern ports have been closed by storms and floods. The only chokepoint that has not recently been disrupted is the Straits of Gibraltar, which connects the Mediterranean with the Atlantic.

The Middle East and North Africa region is particularly vulnerable, the report found, because it has the highest dependency on food imports in the world and is encircled by maritime bottlenecks. It also depends heavily on wheat imports from the Black Sea.

In 2010, a severe heatwave in Russia badly hit the huge grain harvest, leading the government to impose an export ban. As a result, prices spiked in 2011 and this was a significant factor in the Arab Spring conflicts. Other factors were important too, said Wellesley, but she said: “At the start, it was about the price of bread.”

The risks posed by the chokepoints is rising as the international trade in food is growing but also because of global warming, according to the report. It says climate change is bringing more storms, droughts and heatwaves which can block chokepoints and also damage already ageing infrastructure. But it is also likely to fuel armed conflicts, which can also shut down the bottlenecks.

Other countries especially at risk from disruption are poorer nations reliant on imports such as Ethiopia, Kenya, Tanzania and Sudan, as well as richer nations like Japan and South Korea, according to the report.

China is also a major importer but it has done the most to mitigate its exposure to chokepoint risk, the report found. It has diversified its supply routes, for example building a railway across South America to lessen reliance on the Panama canal. Chinese companies also own and operate ports around the world.

The report recommends increased global cooperation to plan for food supply crises and more investment in crucial infrastructure. Wellesley said: “The straits of Hormuz [which Iran has threatened to close] is a really interesting example of where the energy sector is sitting up and taking notice – the food sector should be doing the same. Those same countries that rely on Hormuz to export their oil rely almost entirely on the same strait for their food supply.”

Paris climate agreement: World leaders slam Trump decision

World leaders on Thursday condemned President Trump's decision to pull out of the Paris climate agreement.

Although the president said he is willing to work for a better deal, France, Italy and Germany said in a joint statement that the accord can not be re-negotiated.

German Chancellor Angela Merkel, French President Emmanuel Macron and Italian Prime Minister Paolo Gentiloni urged allies to "speed up" efforts to fight against climate change and said they would do more to help poorer countries.

Paris City Hall was illuminated in green Thursday night following Trump's announcement.

Canadian Prime Minister Justin Trudeau took to Twitter to criticize Trump's decision, saying his country is "deeply disappointed."

"We are all custodians of this world, and that is why Canada will continue to work with the U.S. at the state level, and with other U.S. stakeholders, to address climate change and promote clean growth," Trudeau said in a statement.

British Prime Minister Theresa May's office said she "expressed her disappointment" in a phone call with Trump, and "stressed that the U.K. remained committed to the Paris Agreement."

Scotland's First Minister Nicola Sturgeon called the decision "irresponsible."

Prime Minister of Denmark Lars Rasmussen said it was a "sad day for the world."

The European Union's top climate change official echoed Rasmussen's sentiments, calling it "a sad day for the global community."

"The EU deeply regrets the unilateral decision by the Trump administration to withdraw the US from the Paris Agreement," European Union Climate Action and Energy Commissioner Miguel Arias Cañete said in a statement.

Former Mexican president Vincente Fox unleashed a tweetstorm, saying Trump has "surrendered the hopes and future of a nation."

“He’s declaring war on the planet itself,” Fox added.

Belgian Prime Minister Charles Michel also weighed in: "I condemn this brutal act. ... Leadership means fighting climate change together. Not forsaking commitment."

The 197-member climate agreement requires every country to establish ambitious targets to reduce greenhouse gasses. But those targets are largely voluntary, and Trump has already made clear that he views environmental regulations as an obstacle to his goal of creating jobs and ensuring energy independence.

Under the terms of the agreement, the earliest a nation can formally withdraw is November, 2020 — the same month Trump will run for re-election.

Earlier Thursday, Russia said it supported the Paris deal. "President (Vladimir) Putin signed this convention in Paris. Russia attaches great significance to it," Kremlin spokesman Dmitry Peskov said during a call with reporters, the Independent reported.

"At the same time, it goes without saying that the effectiveness of this convention is likely to be reduced without its key participants," he said.

Chinese Premier Li Keqiang promised to work with the EU to uphold the Paris climate accord, saying there is a "global consensus" and an "international responsibility” to fight climate change, the Associated Press reported.

"China in recent years has stayed true to its commitment,” he said in Berlin, referring to the Paris climate deal. China has been actively promoting the Paris agreement and was one of the first countries to ratify it, he said.

 

  • Published in World

Climate change: ‘human fingerprint’ found on global extreme weather

Global warming makes temperature patterns that cause heatwaves, droughts and floods across Europe, north America and Asia more likely, scientists find.

The fingerprint of human-caused climate change has been found on heatwaves, droughts and floods across the world, according to scientists.

The discovery indicates that the impacts of global warming are already being felt by society and adds further urgency to the need to cut carbon emissions. A key factor is the fast-melting Arctic, which is now strongly linked to extreme weather across Europe, Asia and north America.

Rising greenhouse gases in the atmosphere have long been expected to lead to increasing extreme weather events, as they trap extra energy in the atmosphere. But linking global warming to particular events is difficult because the climate is naturally variable.

The new work analysed a type of extreme weather event known to be caused by changes in “planetary waves” – such as California’s ongoing record drought, and recent heatwaves in the US and Russia, as well as severe floods in Pakistan in 2010.

Planetary waves are a pattern of winds, of which the jet stream is a part, that encircle the northern hemisphere in lines that undulate from the tropics to the poles. Normally, the whole wave moves eastwards but, under certain temperature conditions, the wave can halt its movement. This leaves whole regions under the same weather for extended periods, which can turn hot spells into heatwaves and wet weather into floods.

This type of extreme weather event is known to have increased in recent decades. But the new research used observations and climate models to show that the chances of the conditions needed to halt the planetary waves occurring are significantly more likely as a result of global warming.

“Human activity has been suspected of contributing to this pattern before, but now we uncover a clear fingerprint of human activity,” said Prof Michael Mann, at Pennsylvania State University in the US and who led the study published in the journal Scientific Reports.

Large scale wind patterns are largely driven by the temperature difference between the poles and the tropics. But global warming is altering this difference because the Arctic is heating up faster than lower latitudes and because land areas are heating up faster than the oceans.

Recent changes in the Arctic are particularly striking, with record low levels of ice cover and extremely unusual high temperatures. “Things in the Arctic are happening much faster than we expected,” said Prof Stefan Rahmstorf, also at PIK.

“It is not just a problem of nature conservation or polar bears, it is about a threat to human society that comes from these rapid changes,” he said. “This is because it hits us with increasing extreme events in the highly populated centres in the mid-latitudes. It also affects us through sea level rise, which is hitting shores globally. So these changes that are going on in the Arctic should concern everyone.”

Other climate research, called attribution, is increasingly able to calculate how much more likely specific extreme weather events have been made by global warming. For example, the heatwave in south-eastern Australia in February was made twice as likely by climate change, while Storm Desmond, which caused heavy flooding in the UK in 2015, was made 40% more likely.

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