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.


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.”

Heat Wave Ruled Out in Cuba

Havana, Jul 23 (Prensa Latina) The possibility of a heat wave in Cuba in the next few days was ruled out by a specialist from the Climate Center of the Meteorological Institute of the island, the daily Granma points out today.

The prevalence of very warm thermal sensations refers to particular atmospheric situations in mid-latitudes and continental zones, when temperatures reach values above 40 degrees Celsius, Ramon Perez, a researcher at the scientific institution, told the newspaper.

This reality, together with the prevailing low humidity, leads to the death of human beings from dehydration and other causes, he explained.

In particular, Cuba, due to its insular condition, makes such events improbable, as the sea breeze will always be a mitigating factor for not recording such extreme scenarios, to which is added the usual cooling of the atmosphere caused by the typical rains of summer afternoons, Perez added.

According to the expert, the heat wave concept depends not only on the behavior of the temperatures, but also on the impact they cause.

When comparing what happened in previous summers, he declared that in June there was no record of absolute maximum, while the monthly average was very close to the norm with an anomaly of 0.2 degrees Celsius below the usual.

Nor, he also added, in the first two decades of July there is any report of new primacy of maximum. The highest record registered to date is 37.3 degrees, in Veguitas, Granma, on the 17th, he commented.

During July of the 2015, 11 heat records were set, he recalled.

Although the current summer period in Cuba remains within the normal range, between 1951 and 2010 the average temperature at the stage increased by 0.8 degrees Celsius, which confirms the trend towards a warmer climate in this country, he warned.

This situation progressively leads us to extreme heat values over the years, but at least for now our insular condition protects us from the so-called waves, he concluded.

  • Published in Cuba

Protecting tropical forest carbon stocks may not prevent large-scale species loss

Tropical forests are rich in carbon and biodiversity. As the world seeks to curb human-induced climate change, will protecting the carbon of tropical forests also ensure the survival of their species?

A study published today in the leading journal Nature Climate Change suggests the answer to this question is far from straightforward.

Investments designed to prevent massive carbon losses from the world's tropical forests are likely to be least effective for biodiversity in the most ecologically valuable forests, according to research by an international team, led by scientists from Lancaster University's Environment Centre (UK) and The Brazilian Agricultural Research Corporation (EMBRAPA).

Alarmingly, in these forests, up to 77% of species that would have been protected through biodiversity conservation were not protected through measures focused solely on protecting carbon stocks.

"Securing tropical forest carbon should remain a central conservation objective," said Dr. Gareth Lennox, co-lead author of the study and a Senior Research Associate at Lancaster University. "Not only will this slow climate change but it also has the potential to safeguard the unique and irreplaceable wildlife that inhabits these ecosystems. However, to ensure that those species survive, biodiversity needs to be treated as a priority -- alongside carbon -- of conservation efforts."

The global importance of tropical forests

Tropical forests store more than a third of the world's land carbon. When released to the atmosphere by humans, through forest disturbances -- such as logging and fires -- and deforestation, this carbon exacerbates global warming.

Protecting tropical forest carbon is therefore a key aim of international initiatives to blunt climate change and has attracted tens of billions of dollars of financing.

Tropical forests are also the world's most biodiverse ecosystems, harbouring more than two-thirds of Earth's land species, but the implications for biodiversity of investments focused only on protecting carbon stocks have until now remained unclear.

The relationship between carbon and biodiversity

The international team, comprised of scientists from Brazil, Europe and Australia, spent 18 months measuring the carbon content and species richness of plants, birds and dung beetles in 234 tropical forests in the Brazilian Amazon.

In a scientific first, they assessed carbon and biodiversity levels in forests spanning the range of human impacts, from those minimally disturbed to those recovering after complete clearance of vegetation.

Using these unprecedented data, the team found that more carbon meant more biodiversity in severely damaged forests, as anticipated. Contrary to expectations, however, where human impacts were less intense, increasing amounts of carbon did not come with more species.

Co-lead author Dr. Joice Ferreira from EMBRAPA outlined the significance of these findings: "The changing relationship between carbon and biodiversity across forests that have suffered different kinds of human disturbances explain our findings. As cleared and highly disturbed sites recover from the effects of agricultural use and severe wildfires, biodiversity also recovers. However, this linkage between carbon and biodiversity breaks down mid-recovery. The result: Forests with the greatest carbon content do not necessarily house the most species, meaning carbon-focused conservation can miss large swathes of tropical forest biodiversity."

Focusing on both biodiversity and carbon

Alongside these more alarming findings, the study offered hope for aligning carbon and biodiversity conservation efforts. "Although trade-offs are inevitable, conflicts between carbon and biodiversity can be reduced by more integrated planning," said Dr. Toby Gardner, Senior Research Fellow at the Stockholm Environment Institute and study co-author. "By considering carbon and biodiversity together, we found, for example, that the number of large tree species that can be protected can be increased by up to 15% relative to a carbon-only approach for just a 1% reduction in carbon coverage."

While promising remote sensing tools are being developed to measure forest carbon, increasing biodiversity protection through carbon investments is only possible with extensive field monitoring. Yet, in Brazil, progress in this area is sorely lacking. Joice Ferreira described the situation, "As a megadiverse country, Brazil needs additional, integrated mechanisms to guarantee comprehensive monitoring of its biodiversity. Unfortunately, with government actions reducing scientific capacity and environmental protection, we are witnessing the exact opposite."

Ultimately, curbing climate change requires the safeguarding of biodiversity. Co-author Professor Jos Barlow from Lancaster University explained why, "Biodiversity and climate change are inextricably linked in tropical forests. A warming climate and changing rainfall patterns will lead to the extinction of many tropical species, while it is within tropical biodiversity itself that forest carbon resides. Species-poor forests will eventually become carbon-poor. Therefore, tackling the climate crisis requires that both tropical forest carbon and tropical forest species are protected together."

Cuba’s action plan for dealing with climate change

Cuba’s “Project Life” action plan outlines eleven projects to help the island nation adapt to climate change:

Project 1: Identify and implement actions and projects, of a comprehensive, ongoing nature, to adapt to climate change that are needed to reduce existing vulnerability in 15 identified priority zones. The threatened population, their physical safety and food security, and the development of tourism must be considered when determining the order of these actions.

Project 2: Implement legal norms needed to execute the state plan, as well as assure their strict enforcement, with particular attention to measures directed toward vulnerability of constructed properties, prioritising threatened coastal communities.

Project 3: Conserve, maintain and recover the Cuban archipelago’s sandy beaches, prioritising those urbanised for tourist use and reducing the structural vulnerability of constructed properties.

Project 4: Ensure the availability and efficient use of water as part of confronting drought, on the basis of technology for conservation and satisfying the demands of locations. Improve water infrastructure and its maintenance, while taking action to measure the efficient and productive use of water.

Project 5: Direct reforestation towards providing maximum protection of soils and water, in terms of quantity and quality, as well as the recovery of the most affected mangroves. Prioritise reservoirs, canals and the regulatory banks of tributaries leading to the island’s principal bays and coasts.

Project 6: Stop deterioration, and renovate and protect coral reefs throughout the archipelago, with priority for those bordering the insular platform, and protect urbanised beaches used for tourism purposes. Avoid overfishing of species that benefit corals.

Project 7: Maintain and add territorial and urban land use stipulations to plans in the Macro-project on Dangers and Vulnerability of Coastal Zones 2050-2100, as well as in the Studies of Dangers, Vulnerability and Risks in the disaster preparedness effort. Employ this information as an early warning to make decisions.

Project 8: Implement and supervise climate change adaptation and mitigation measures in sector policies for programs, plans and projects linked to food security, renewable energy, energy efficiency, land use, fishing, agriculture, health, tourism, construction, transport, industry and the comprehensive management of forests.

Project 9: Strengthen monitoring systems, vigilance and early warning plans to systematically evaluate the condition and quality of coastal zones, water, drought and forests, as well as human and plant health.

Project 10: Prioritise measures and actions to increase risk perception, understanding of, and participation by the entire population in confronting climate change and a culture that promotes water conservation.

Project 11: Manage and use available international financial resources, both those from global and regional climate funds and those from bilateral sources, to make investments, carry out actions and implement projects related to the tasks outlined in the state plan.

  • Published in Cuba

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.  

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 Turn Earth into Venus: Stephen Hawking

The British physicist said Venus was once an inhabitable Earth-like planet, but greenhouse gases raised its surface temperatures to boiling point – and beyond.

In the second episode of his new series "Stephen Hawking's Favorite Places," the British physicist warns Earth could soon become as hot as Venus if action to halt climate change is not taken immediately.

RELATED: Stephen Hawking Says AI Can 'Outperform Humans'

Hawking says Venus was once an Earth-like planet with surface water, mild temperatures and an appropiate atmosphere. According to NASA, Venus was an inhabitable planet for a period of about two billion years as recently as four billion years ago.

Now temperatues on Venus reach 250°C with powerful 300mph winds. Hawking says a greenhouse effect burned the planet's oceans and lands, and that something similar could happen right here on Earth if climate change continues unabated.

"Next time you meet a climate-change denier, tell them to take a trip to Venus; I will pay the fare," says the physicist in his show.

Hawking has severely criticized Trump's decision last year to pull the United States out of the Paris Agreement. The US president has stated before that this climate pact puts the US economy at a disadvantage, even denying that climate change is a real thing and stating that he cares not for the citizens of Paris, but only those of the United States.

The Paris climate agreement is an international effort to reduce greenhouse gas emissions and was signed by 195 nations in 2015.

In the Starmus Festival last year, Hawking said Trump's decision was "the most serious and wrong decision on climate change this world has seen." He also said that the human race would have to colonize outer space in the next 200 to 500 years if we are to survive as species.

Since then, Hawking has stated multiple times his hopes for a new era of space exploration, in which nations unite toward a single goal.

"It is clear we are entering a new space age. We are standing at the threshold of a new era. Human colonisation and other planets is no longer science fiction, it can be science fact."

The scientist is currently working on Breakthrough Starshot, a project that could send "a ground-based light beamer pushing ultra-light nanocrafts – miniature space probes attached to lightsails – to speeds of up to 100 million miles an hour" to Alpha Centauri, the closest star system, in just 20 years.

"Stephen Hawking's Favorite Places" won an Emmy last year and is available for streaming at Curiosity Stream.

Arctic clouds highly sensitive to air pollution

In 1870, explorer Adolf Erik Nordenskiöld, trekking across the barren and remote ice cap of Greenland, saw something most people wouldn't expect in such an empty, inhospitable landscape: haze.

Nordenskiöld's record of the haze was among the first evidence that air pollution around the northern hemisphere can travel toward the pole and degrade air quality in the Arctic. Now, a study from University of Utah atmospheric scientist Tim Garrett and colleagues finds that the air in the Arctic is extraordinarily sensitive to air pollution, and that particulate matter may spur Arctic cloud formation. These clouds, Garrett writes, can act as a blanket, further warming an already-changing Arctic.

"The Arctic climate is delicate, just as the ecosystems present there," Garrett says. "The clouds are right at the edge of their existence and they have a big impact on local climate. It looks like clouds there are especially sensitive to air pollution." The study is published in Geophysical Research Letters.

Pollution heading north

Garrett says that early Arctic explorers' notes show that air pollution has been traveling northward for nearly 150 years or more. "This pollution would naturally get blown northward because that's the dominant circulation pattern to move from lower latitudes toward the poles," he says. Once in the Arctic, the pollution becomes trapped under a temperature inversion, much like the inversions that Salt Lake City experiences every winter. In an inversion, a cap of warm air sits over a pool of cold air, preventing the accumulated bad air from escaping.

Others have studied which regions contribute to Arctic pollution. Northeast Asia is a significant contributor. So are sources in the far north of Europe. "They have far more direct access to the Arctic," Garrett says. "Pollution sources there don't get diluted throughout the atmosphere."

Scientists have been interested in the effects of pollution on Arctic clouds because of their potential warming effect. In other parts of the world, clouds can cool the surface because their white color reflects solar energy back out into space. "In the Arctic, the cooling effect isn't as large because the sea-ice at the surface is already bright," Garrett says. "Just as clouds reflect radiation efficiently, they also absorb radiation efficiently and re-emit that energy back to warm the surface." Droplets of water can form around particulate matter in the air. More particles make for more droplets, which makes for a cloud that warms the surface more.

Seeing through the clouds

But quantifying the relationship between air pollution and clouds has been difficult. Scientists can only sample air pollution in clouds by flying through them, a method that can't cover much ground or a long time period. Satellite images can detect aerosol pollution in the air -- but not through clouds. "We'll look at the clouds at one place and hope that the aerosols nearby are representative of the aerosols where the cloud is," says Garrett. "They're not going to be. The cloud is there because it's in a different meteorological air mass than where the clear sky is."

So Garrett and his colleagues, including U graduate Quentin Coopman, needed a different approach. Atmospheric models, it turns out, do a good job of tracking the movements of air pollution around the Earth. Using global inventories of pollution sources, they simulate air pollution plumes so that satellites can observe what happens when these modeled plumes interact with Arctic clouds. The model allowed the researchers to study air pollution and clouds at the same time and place and also take into account the meteorological conditions. They could be sure the effects they were seeing weren't just natural meteorological variations in normal cloud-forming conditions.

Highly sensitive clouds

The research team found that clouds in the Arctic were two to eight times more sensitive to air pollution than clouds at other latitudes. They don't know for sure why yet, but hypothesize it may have to do with the stillness of the Arctic air mass. Without the air turbulence seen at mid-latitudes, the Arctic air can be easily perturbed by airborne particulates.

One factor the clouds were not sensitive to, however, was smoke from forest fires. "It's not that forest fires don't have the potential," Garrett says, "it's just that the plumes from these fires didn't end up in the same place as clouds." Air pollution attributable to human activities outpaced the influence of forest fires on Arctic clouds by a factor of around 100:1.

This gives Garrett hope. Particulate matter is an airborne pollutant that can be controlled relatively easily, compared to pollutants like carbon dioxide. Controlling current particulate matter sources could ease pollution in the Arctic, decrease cloud cover, and slow down warming. All of those gains could be offset, other researchers have suggested, if the Arctic becomes a shipping route and sees industrialization and development. Emissions from those activities could have a disproportionate effect on Arctic clouds compared to emissions from other parts of the world, Garrett says.

"The Arctic is changing incredibly rapidly," he says. "Much more rapidly than the rest of the world, which is changing rapidly enough."

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