Climate Change Could Hit Point of No Return by 2035

London, Sep 1 (Prensa Latina) Earth could go through a point of no return by 2035 if governments do not act decisively when it comes to fighting climate change, warns a study published in the Earth System Dynamics magazine.

Scientists at the University of Oxford say it would be unlikely to limit global warming to below two degrees Celsius by 2100 and consider that the deadline to reduce it to 1.5 degrees has already passed, unless radical climate action is taken.

The researchers wanted to find the last possible year to start reducing greenhouse gas emissions before it is too late.

In this regard, the concept of point of no return has the advantage of containing useful temporary information to report about the urgency of taking climate measures, says Matthias Aengenheyster, the study's lead author.

Through the use of information on climate models, the team determined the deadline to initiate actions, in order to keep global warming likely (with a probability of 67 percent) below two degrees Celsius by 2100.

This depends on how fast humanity can reduce emissions with the use of more renewable energy.

According to experts, the point of no return has already been exceeded for the most modest climate action scenario, where the proportion of renewable resources increases by two percent each year.

However, they consider that the elimination of greenhouse gases from the atmosphere, through the use of negative emission technology, could give the Earth a little more time: between six and 10 years.

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Domino-effect of climate events could move Earth into a ‘hothouse’ state

A domino-like cascade of melting ice, warming seas, shifting currents and dying forests could tilt the Earth into a “hothouse” state beyond which human efforts to reduce emissions will be increasingly futile, a group of leading climate scientists has warned.

This grim prospect is sketched out in a journal paper that considers the combined consequences of 10 climate change processes, including the release of methane trapped in Siberian permafrost and the impact of melting ice in Greenland on the Antarctic.

The authors of the essay, published in Proceedings of the National Academy of Sciences, stress their analysis is not conclusive, but warn the Paris commitment to keep warming at 2C above pre-industrial levels may not be enough to “park” the planet’s climate at a stable temperature.

They warn that the hothouse trajectory “would almost certainly flood deltaic environments, increase the risk of damage from coastal storms, and eliminate coral reefs (and all of the benefits that they provide for societies) by the end of this century or earlier.”

“I do hope we are wrong, but as scientists we have a responsibility to explore whether this is real,” said Johan Rockström, executive director of the Stockholm Resilience Centre. “We need to know now. It’s so urgent. This is one of the most existential questions in science.”

Rockström and his co-authors are among the world’s leading authorities on positive feedback loops, by which warming temperatures release new sources of greenhouse gases or destroy the Earth’s ability to absorb carbon or reflect heat.

Their new paper asks whether the planet’s temperature can stabilise at 2C or whether it will gravitate towards a more extreme state. The authors attempt to assess whether warming can be halted or whether it will tip towards a “hothouse” world that is 4C warmer than pre-industrial times and far less supportive of human life.

Katherine Richardson from the University of Copenhagen, one of the authors, said the paper showed that climate action was not just a case of turning the knob on emissions, but of understanding how various factors interact at a global level.

“We note that the Earth has never in its history had a quasi-stable state that is around 2C warmer than the preindustrial and suggest that there is substantial risk that the system, itself, will ‘want’ to continue warming because of all of these other processes – even if we stop emissions,” she said. “This implies not only reducing emissions but much more.”

New feedback loops are still being discovered. A separate paper published in PNAS reveals that increased rainfall – a symptom of climate change in some regions - is making it harder for forest soils to trap greenhouse gases such as methane.

Previous studies have shown that weakening carbon sinks will add 0.25C, forest dieback will add 0.11C, permafrost thaw will add 0.9C and increased bacterial respiration will add 0.02C. The authors of the new paper also look at the loss of methane hydrates from the ocean floor and the reduction of snow and ice cover at the poles.

Rockström says there are huge gaps in data and knowledge about how one process might amplify another. Contrary to the Gaia theory, which suggests the Earth has a self-righting tendency, he says the feedbacks could push the planet to a more extreme state.

As an example, the authors say the loss of Greenland ice could disrupt the Gulf Stream ocean current, which would raise sea levels and accumulate heat in the Southern Ocean, which would in turn accelerate ice loss from the east Antarctic. Concerns about this possibility were heightened earlier this year by reports that the Gulf Stream was at its weakest level in 1,600 years.

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Currently, global average temperatures are just over 1C above pre-industrial levels and rising at 0.17C per decade. The Paris climate agreement set actions to keep warming limited to 1.5C-2C by the end of the century, but the authors warn more drastic action may be necessary.

“The heatwave we now have in Europe is not something that was expected with just 1C of warming,” Rockström said. “Several positive feedback loops are already in operation, but they are still weak. We need studies to show when they might cause a runaway effect.

Another climate scientist – who was not involved in the paper – emphasised the document aimed to raise questions rather than prove a theory. “It’s rather selective, but not outlandish,” said Prof Martin Siegert, co-director of the Grantham Institute. “Threshold and tipping points have been discussed previously, but to state that 2C is a threshold we can’t pull back from is new, I think. I’m not sure what ‘evidence’ there is for this – or indeed whether there can be until we experience it.”

Rockström said the question needed asking. “We could end up delivering the Paris agreement and keep to 2C of warming, but then face an ugly surprise if the system starts to slip away,” he said. “We don’t say this will definitely happen. We just list all the disruptive events and come up with plausible occurrences … 50 years ago, this would be dismissed as alarmist, but now scientists have become really worried.”

“In the context of the summer of 2018, this is definitely not a case of crying wolf, raising a false alarm: the wolves are now in sight,” said Dr Phil Williamson, a climate researcher at the University of East Anglia. “The authors argue that we need to be much more proactive in that regard, not just ending greenhouse gas emissions as rapidly as possible, but also building resilience in the context of complex Earth system processes that we might not fully understand until it is too late.”

Europe's record temperature of 48C could be beaten this weekend

Britain is basking in 31C heat, three people have died from heatstroke in Spain as the mercury reached the mid-40s, and a mountain glacier in Sweden has melted so much that its peak is no longer the country’s highest point.

Alex Burkill, a Met Office meteorologist, said that despite the cooler temperatures of recent days “it is not the end of the hot weather for the summer” as sunshine returns to most of the country.

A yellow severe warning for thunderstorms was in place for some parts of England and Scotland until 9pm on Friday.

The Met Office said: “Some flooding of a few homes and businesses is possible, leading to some damage to buildings or structures. There is a good chance driving conditions will be affected by spray, standing water and/or hail, leading to longer journey times by car and bus. Some short-term loss of power and other services is likely.”

Sun-drenched British holidaymakers are enjoying record temperatures on the continent during their summer breaks. Tourists are being urged to avoid the sun during the hottest part of the day and remember that children are particularly susceptible to the heat.

People cool off at the beach in Benidorm, Spain.People cool off at the beach in Benidorm, Spain. Photograph: Heino Kalis/Reuters

Eight places in Portugal broke local temperature records on Friday as a wave of heat from North Africa swept across the Iberian peninsula and officials predicted the scorching temperatures could get even worse over the weekend.

Temperatures built to around 45C (113 F) in many inland areas of Portugal, and were expected to peak at 47C (116.6F) in some places on Saturday. Large sections of Portugal are on red alert on the country’s civil protection agency’s danger scale.

The highest temperature recorded on Thursday, when the heat began to rise, was 45.2 C (113.4 F) near Abrantes, a town 150km (93 miles) north-east of the capital, Lisbon, the country’s weather agency IPMA said.

In Spain three men died of heatstroke. A middle-aged man in Barcelona was found collapsed on a street and taken to hospital where he later died. Two other men – a roadworker in his 40s and a 78-year-old pensioner – also died from heatstroke.

 

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Need to save coral reefs

Flood damage would double without coral reefs, proves study

Loss of coral reefs around the world would double the damage from coastal flooding, and triple the destruction caused by storm surges, researchers said today.

Coupled with projected sea level rise driven by global warming, reef decline could see flooding increase four-fold by century’s end, they reported in the journal Nature Communications.

Without coral to help absorb the shock, a once-in-a-century cyclone would wreak twice the havoc, with the damage measured in the tens of billions of dollars, the team calculated.

“Coral reefs serve as natural, submerged breakwaters that reduce flooding by breaking waves and reducing wave energy,” said Michael Beck, lead scientist at The Nature Conservancy research and environmental group, and a professor at the University of California in Santa Cruz.

“Unfortunately, we are already losing the height and complexity of shallow reefs around the world, so we are likely already seeing increases in flood damages along many tropical coasts,” he told AFP.

Coral is also highly sensitive to spikes in water temperature, which have become sharper and more frequent with climate change.

Global coral reefs risk catastrophic die-off if Earth’s average surface temperature increases two degrees Celsius (3.6 degrees Fahrenheit) above pre-industrial levels, earlier research has shown.

Combining coastal flooding and economic models, the new study calculated - country by country - the value of coral reefs as a barrier against storm-related wreckage.

Globally, seaside flooding is estimated to cause nearly USD 4 billion dollars (3.4 billion Euros) a year in damages.

With the erosion of the top metre (three feet) of coral reefs worldwide, that figure rises to USD 8 billion, Beck and his colleagues found.

“The topmost living corals will die and can break off very quickly,” said Beck. The countries most at risk from coral reef loss are Indonesia, the Philippines, Malaysia, Mexico and Cuba, each of which could avoid USD 400 million in damage per year if reefs are maintained.

Saudi Arabia, the United States, Taiwan and Vietnam would also become significantly more vulnerable to flooding with severe coral erosion. “When we consider the devastating impact of tropical storms in just the past few years - Hurricanes Irma and Maria, Typhoon Haiyan - the effects would be much worse without coral reefs,” Beck said.AFP

Ocean warming threatens kelp forests

Increasing sea temperatures in the northeast Atlantic Ocean have led to lower growth rates and decreased local biodiversity within coastal kelp forests, new research has revealed.

The research shows that the amount of carbon fixed by kelp forests and released as ‘leaf litter’ had been previously underestimated and, crucially, that kelp forests in cold waters typically store and release two to three times more carbon than those in warm waters. Kelp forests generally occur in cold, nutrient-rich water and are among the most productive ecosystems on Earth, absorbing vast amounts of carbon dioxide in order to grow. However, recent significant warming of some parts of the Atlantic mean that sea temperatures are no longer optimal for kelp growth.

Kelp grows more slowly in warmer sea temperatures
Kelp grows more slowly in warmer sea temperatures

© Marine Biological Association

Dr Dan Smale of the Marine Biological Association, who co-led the research, has been studying kelp forest ecosystems in the UK and elsewhere for a decade. He says: “Some kelp species can grow incredibly quickly, providing fuel for coastal food webs that in turn support a wide range of marine life, including fish, crabs, birds and mammals. We knew that kelp forests fix and release considerable amounts of carbon, but until now we didn’t know exactly how much energy flows through these habitats and just how strongly ocean temperature affects this process”  

The team used scientific diving to perform surveys and experiments at eight locations, spanning 900 kilometres of UK coastline, from northern Scotland to southwest England, to determine how ocean temperatures affect kelp forest growth rates.

The observations have important implications for the future of oceans and management of global warming.

“The study comes as the debate of how we manage coastal ecosystems to tackle climate change intensifies, and our results suggest kelp forests have a more important role to play than previously thought,” Dr Smale said.

In a separate, related study, the team also showed that ocean warming has led to changes in habitat structure, as different kelp species respond to increased sea temperature in different ways. Changes in the density and identity of kelp species have caused changes in the number and diversity of plants and animals using the forests as habitat. The study highlights how climate change can indirectly impact upon marine biodiversity, by driving changes in the distribution and performance of key habitat-forming species.

“Kelp forests represent critical marine habitats, similar to coral reefs and seagrass meadows, but they are difficult to study and our understanding of how climate change and other pressures are altering these ecosystems remains fairly limited. What is clear, is that they provide habitat and nursery grounds for a wide range of marine life, including fisheries species, and they play a key role in carbon capture and release in coastal waters,” Dr Smale concluded.  

Coral reefs protect coasts from severe storms

Coral reefs can naturally protect coasts from tropical cyclones by reducing the impact of large waves before they reach the shore, according to scientists.

Tropical cyclones wreak havoc on coastal infrastructure, marine habitats and coastal populations across the world. However, Dr. Michael Cuttler, from the ARC Centre of Excellence for Coral Reef Studies (Coral CoE) at The University of Western Australia (UWA), says that for coastlines facing a direct cyclone impact, a fringing reef can protect the beach from extensive erosion.

"Reefs can effectively protect shorelines because of their ability to cause waves to break offshore, thus limiting the energy impacting the coastline," he said.

Dr. Cuttler and several of his Coral CoE colleagues studied Ningaloo Reef -- Australia's largest fringing reef system, and a UN World Heritage site -- during Tropical Cyclone Olwyn in 2015. Olwyn was a Category 3 severe tropical cyclone that caused extensive damage along the coast of Western Australia.

The team observed that the shoreline remained largely unscathed because of the protection provided by its offshore reef.

"The large waves generated by the cyclone were effectively dissipated by the reef situated offshore," Dr. Cuttler explained.

"The little erosion that did occur was due to smaller waves that were generated by wind within the lagoon."

The shape, or geomorphology, of the reef -- with its steep forereef slope, shallow reef crest and reef flat, and relatively shallow lagoon -- is representative of most fringing reefs worldwide.

"In this study, we also compared similar cyclone impacts on coastlines without reefs and found that these beaches were eroded up to ten times more than the beach at Ningaloo," Dr. Cuttler said.

While the findings of Dr. Cuttler's study indicated that coral reefs can effectively protect coastlines from tropical cyclones and other large wave impacts, it also suggested that for reef systems with lagoons, local wind effects cannot be ignored when attempting to model or predict the impact of cyclones.

He also warned that the ability of reefs to protect adjacent coastlines was threatened by both sea level rise and slowing rates of reef accretion.

"These changes may ultimately increase the amount of wave energy reaching the coastline and potentially enhance coastal erosion," he said.

Few studies before have measured the hydrodynamic conditions and morphological responses of such a coastline in the presence of a tropical cyclone.

Dr. Cuttler and his Coral CoE colleagues found the results could be used to assess coastal hazards facing reef-fringed coastlines due to extreme tropical cyclone conditions, and would become increasingly relevant as climate change alters the status of coral reefs globally.

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.

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