Feedback climate loops very bad news

 

Fiercer wildfires in drying forests are occurring globally, as seen in this image from Indonesia in August 2026. Photograph: Mast Irham/EPA

From The Guardian

Rising global temperatures caused by the burning of fossil fuels are transforming the world’s forests, wetlands and tundra to the point they are releasing emissions that could further worsen global heating by as much as 30%, a new study has found.

As the world heats up, permafrost in the high latitudes is thawing, fiercer wildfires are burning in drying forests and wetlands and lakes are warming. All of these changes are themselves causing the release of planet-heating methane and carbon dioxide locked in trees and soils, therefore worsening the climate crisis, the paper states.

While scientists have long known of these “feedback loops” that amplify the impact of direct pollution from burning coal, oil and gas, the emissions from natural sources are largely unaccounted for in climate projections.

This additional heating is, however, significant, researchers found, with emissions from natural sources set to amplify global heating by 20% to 30% by the end of this century. This would add an estimated 0.2C to 0.4C to the global average temperature by this time, depending on the overall action taken by countries to combat the climate crisis.

Even small fractions of temperature change across the global climate can greatly change the risk of severe and deadly heatwaves, floods, drought and other impacts.

The United Nations last week conceded the international pact to constrain the global temperature rise to 1.5C above pre-industrial levels will be breached in the next few years, causing climate impacts such as this summer’s record heatwaves and wildfires to “strike faster, hit harder and last longer”.

Yet the increase in the world’s fever will likely be even larger than most projections currently account for, the new research warns, as they do not factor in the methane and CO2 that will spew from permafrost, wetlands, freshwaters and wildfires – the four areas the paper analyzed.

“This hidden multiplier is missing from the models guiding climate policy, so those models are likely underestimating how much warming is coming – and overestimating how much carbon we can still afford to emit,” said Sam Abernethy, a scientist at Spark Climate Solutions who led the research, published in Environmental Research Letters.

The disruption of the world’s carbon cycles is now being seen in “real time”, said Rob Jackson, a Stanford University scientist and study co-author. “The results are a wake-up call, and it’s imperative that they be included in the next generation of climate policies,” he added. “Failure to do so will make meeting the world’s climate goals less and less likely.”

There has been longstanding concern that should global heating melt enough of the Greenland and Antarctic ice sheets, thaw enough permafrost, warp crucial ocean currents and turn the Amazon rainforest into a savannah, the world will career past a series of catastrophic tipping points where the climate system spins wildly outside any sort of restraining human influence.

The planet is getting closer to such a “point of no return” where this runaway global heating becomes reality, a separate study earlier this year warned.

This latest paper makes clear that action by countries to cut fossil fuel pollution will still lessen the amount of additional emissions that come from landscapes. Under the most optimistic climate scenario where emissions are cut quickly, natural sources will add 0.2C of warming, the paper found. Under a worst-case higher emissions scenario, 0.4C will probably be added.

Current policies put in place by governments are likely to see the global temperature rise to 2.6C above pre-industrial times, according to Climate Action Tracker. This will probably cause severe disruption and hardship to billions of people through sea level rise, crop losses and other consequences.

“One of the most troubling aspects of climate change is that warming can trigger natural processes that cause still more warming,” said Bill Ripple, an ecologist at Oregon State University who helped author the research earlier this year on runaway heating. He was not involved in the new paper, which he called “important”.

“This does not mean that a Hothouse Earth trajectory is inevitable, but it provides another warning about the possibility of reinforcing feedbacks that can amplify the warming humans initiate,” he said.

“The paper also reminds us why every fraction of a degree matters. The more we warm the planet, the more we risk activating natural processes that add still more greenhouse gases to the atmosphere. This makes rapid reductions in fossil fuel emissions even more urgent.”

These feedbacks are causing accelerated heating.  

Meanwhile, Australia is approving new and expanded coal and gas extraction, the US is cancelling wind farms and opposes EVs, the UK wants to licence new North Sea oil exploration, Europe is dragging its feet on the transition to EVs, and China, Indonesia and India are still building new coal power stations.  Politicians clearly do not accept the urgency of the change needed.

The end of oil

From The Conversation

US President Donald Trump is a longtime climate denier and oil industry ally, who sums up his own energy policy as “drill, baby, drill”. Yet he is doing more than almost anyone to speed up the global shift from fossil fuels to clean energy and electric vehicles (EVs).

After the US and Israel struck Iran in late February, Tehran closed the Strait of Hormuz and triggered the largest disruption of oil supply in history.

Ironically for Trump and his oil industry donors, this crisis may be an irreversible tipping point for clean energy. For years, fossil fuel advocates spruiked oil, gas and coal as “reliable” energy. That narrative has been reversed. Fossil fuels have become expensive and unreliable, while renewables are cheap, reliable and secure.

For the first time ever, more than 50 nations will gather next week in Colombia to hash out how to wind down and end their dependence on coal, oil and gas. The history-making conference was planned before the Iran war. But this year’s energy crisis has greatly raised the stakes.

The oil crisis is real

Iran’s closure of the narrow Strait of Hormuz stopped oil tankers reaching their destinations. But that wasn’t all. More than 60 gas and oil sites have been damaged in the conflict so far. Even if a durable ceasefire is reached, these impacts will reverberate for months and years to come.

Around 80% of the trapped crude oil was destined for the Asia-Pacific. Faced with dwindling supply, the region’s governments are implementing emergency measures such as sending workers home, banning government travel, rationing fuel and cutting school hours.

The problem is especially bad in the Pacific. Many island nations use diesel for power generation. In response, leaders declared a regional emergency.

Fuel import bills were already a major burden for Pacific nations, leading to efforts to switch to local renewables. Fuel bills could rise by A$933 million in Fiji (nearly three times the healthcare budget).

Scrambling for energy

When energy supplies are disrupted, leaders have three options: find alternate supplies, reduce use or switch to alternatives. In the very short term, countries aim to shore up supply, just as Australian Prime Minister Anthony Albanese did last week in Malaysia.

Countries have also moved to reduce use. This can have lasting effects. During the Middle East oil shocks of the 1970s, oil prices tripled and then doubled again. Authorities responded by improving energy productivity to do more with less. The world’s final oil demand per capita peaked in 1979 and has never recovered.

But the real difference from half a century ago is that fossil fuel alternatives are ready for prime time. Since the 1970s, the price of solar panels has fallen 99.9%, while the cost of wind has fallen 91% since 1984. Battery prices have fallen 99% since 1991.

This means it’s now viable for many nations to switch to these alternatives.

The European Union will accelerate electrification, after its fossil fuel bill increased more than $36 billion since February. France has doubled state aid to help households switch to EVs and electrify home heating. Import-dependent South Korea gets 70% of its crude oil through the Strait of Hormuz. It now plans to double renewables capacity within four years.

Electric vehicles at the tipping point?

This year’s oil shock shows signs of creating an unplanned social tipping point – a threshold for self-propelling change beyond which systems shift from one state to another. Climate scientists warn of climate tipping points which amplify feedback and accelerate warming. But social scientists also point to positive tipping points – collective action that rapidly accelerates climate action.

The rush to EVs is a case in point. In Australia, petrol prices surged almost 50% in March, and diesel more than 70%. It’s no surprise new EV sales are at an all-time high, while secondhand EV sales more than doubled last month.

Australia’s 1.3 million hybrid and battery electric vehicles avoid almost 15 million litres of petrol and diesel use every week.

The rush to electric transport is global. Most new Chinese cars are powered by batteries, not oil. Battery electric vehicles outsold petrol cars for the first time in Europe in January.

A conference to quit fossil fuels

The routine burning of coal, oil and gas is the primary driver of the climate crisis. The world’s highest court last year made clear nations have obligations to stop burning fossil fuels.

But fossil fuels have barely been mentioned in 30 years of global climate negotiations, due in part to blocking efforts by big fossil fuel exporters and lobbyists.

Frustrated by slow progress, a coalition of nations has bypassed global climate talks to discuss how to actually phase out fossil fuels.

The first of these summits will take place next week. More than 50 nations will gather in Santa Marta, Colombia, to discuss a potential standalone treaty to manage fossil-fuel phaseout while protecting workers and financial systems.

Colombian Environment Minister Irene Vélez Torres says it comes at the “best possible moment”, as the oil crisis focuses global attention on fossil fuel dependency.

If next week’s summit produces real momentum to wean off fossil fuels amid the energy crisis, we might look back at it as a social tipping point where early adopters move in earnest – and make it easier for the rest of the world to follow.

Global sea ice plunging to record lows

 From a post by Peter Dynes

Global Sea Ice taking a nose dive to record lows. We are losing over 25,000 tonnes of Ice from the Arctic per second. That’s a lot of Ice. Earth's heating rate will accelerate the more sea ice we lose. The general public is totally unaware of this danger.

2.9 billion birds gone

From Climate & Capitalism

Worldwide, 49 percent of all wild bird species are in steep decline. BirdLife International’s authoritative report, State of the World’s Birds 2022, estimates that there are now nearly three billion fewer wild birds in Canada and the U.S. than a few decades ago, and about 600 million fewer in the European Union. Less comprehensive data is available for the global south, but studies in some South American, African and Asian countries have shown similar declines.

Many accounts of bird population decline simply list multiple possible causes for the decline — wind turbines, urbanization, climate change, logging, wildfires, hunting and even domestic cats. The absence of data on which factors are most important has been a convenient excuse for doing nothing to save the birds.

An important study published in the May 15 issue of PNAS — the Proceedings of the National Academy of Sciences — takes that excuse away. Its title clearly states its principal finding: Farmland Practices Are Driving Bird Population Decline across Europe. The study “provides strong evidence of a direct and predominant effect of farmland practices at large continental scales.”

This is by far the most extensive study to date of bird population dynamics. Over fifty ornithologists, zoologists, biologists and ecologists analyzed decades of population data for 170 bird species in over 20,000 sites in 28 European countries, measuring them against four known pressures on bird populations: agricultural intensification, change in forest cover, urbanization and temperature change.

Between 1980 and 2016 European bird populations as a whole fell by a quarter, but the number of farmland birds dropped by more than half. Areas dominated by large farms saw bigger declines than areas where most farms are smaller.

The single biggest cause of bird declines is chemical-intensive farming. Some birds are killed by pesticides or herbicides, but the most important impacts are loss of food, especially insects and other invertebrates that most bird species depend on, and the spread of fertilizer-intensive monocultures that eliminate shelter and nesting areas. Insect-eating populations declined more than any others.

In short, the collapse of farmland bird populations is closely related to the Insect Apocalypse in the Anthropocene, discussed here recently. The mass slaughter of insects is killing masses of birds.

Industrial agriculture is not, of course, the only driver. Loss of habitat resulting from urban growth and deforestation caused declines, in those areas, of 27.8% and 17.7% respectively. Climate change had mixed effects — northern, cold-preferring birds fell 39.7%, and southern, warm-preferring bird species dropped 17.1%. Overall, however, the most important bird killer is large-scale capitalist agriculture.

The study concludes:

“Considering both the overwhelming negative impact of agricultural intensification and the homogenization introduced by temperature and land-use changes, our results suggest that the fate of common European bird populations depends on the rapid implementation of transformative change in European societies, and especially in agricultural reform.”

800 million Amazon trees felled for beef

Burning forest in Lábrea, Amazonas state in August 2020. Photograph: Christian Braga/Greenpeace

From The Guardian

More than 800m trees have been cut down in the Amazon rainforest in just six years to feed the world’s appetite for Brazilian beef, according to a new investigation, despite dire warnings about the forest’s importance in fighting the climate crisis.

A data-driven investigation by the Bureau of Investigative Journalism (TBIJ), the Guardian, Repórter Brasil and Forbidden Stories shows systematic and vast forest loss linked to cattle farming.

The beef industry in Brazil has consistently pledged to avoid farms linked to deforestation. However, the data suggests that 1.7m hectares (4.2m acres) of the Amazon was destroyed near meat plants exporting beef around the world.

The investigation is part of Forbidden Stories’ Bruno and Dom project. It continues the work of Bruno Pereira, an Indigenous peoples expert, and Dom Phillips, a journalist who was a longtime contributor to the Guardian​​. The two men were killed in the Amazon last year.

Deforestation across Brazil soared between 2019 and 2022 under the then president, Jair Bolsonaro, with cattle ranching being the number one cause. The new administration of Luiz Inácio Lula da Silva has promised to curb the destruction.

Researchers at the AidEnvironment consultancy used satellite imagery, livestock movement records and other data to calculate estimated forest loss over six years, between 2017 and 2022 on thousands of ranches near more than 20 slaughterhouses. All the meat plants were owned by Brazil’s big three beef operators and exporters – JBS, Marfrig and Minerv​a.

To find the farms that were most likely to have supplied each slaughterhouse, the researchers looked at “buying zones”; areas based on transport connections and other factors, including verification using interviews with plant representatives. All the meat plants exported widely, including to the EU, the UK and China, the world’s biggest buyer of Brazilian beef.

The research focused on slaughterhouses in the states of Mato Grosso, Pará and Rondônia, important frontiers of deforestation associated with ranching. It is likely the overall figure for deforestation on farms supplying JBS, Marfrig and Minerva is higher, because they run other plants elsewhere in the Amazon.

All three companies say they operate strict compliance procedures, in an open and honest manner, to ensure they are meeting their sustainable goals.

Nestlé and the German meat company Tönnies, which had supplied Lidl and Aldi, were among those to have apparently bought meat from the plants featured in the study. Dozens of wholesale buyers in various EU countries, some of which supply the catering businesses that serve schools and hospitals, also appeared in the list of buyers.

Nestlé said two of the meatpackers were not currently part of its supply chain, and added: “We may scrutinise business relationships with our suppliers who are unwilling or unable to address gaps in compliance with our standards.”

Tönnies said: “These Brazilian companies process many thousands of animals per year for export,” and claimed it was unclear whether the company was the recipient of products from plants linked to deforestation. Lidl and Aldi said they stopped selling Brazilian beef in 2021 and 2022 respectively.

[The article is long; you can read much more here.]

I beg you:  stop eating beef.  It is one of the biggest things you can do to slash your carbon emissions.  That's before we get to the cruelty and suffering involved in the cattle trade.  When the Amazon forest goes, it will be an irreversible tipping point.  And the whole world will pay.

The Amazon could trigger a cascade of global tipping points

Burnt land and smoke from fires in the Amazon rainforest in Rondonia state, Brazil. (Leonardo Carrato/Bloomberg Creative/Getty Images)

From Science Alert



Deforestation in the Amazon is nearing the point of no return, and if this ecosystem falls, it could flip from a vast carbon sink to a gushing carbon tap. Already, some climate scientists suspect the rainforest is spewing more carbon than it's absorbing.

If the Amazon crosses a critical threshold of self-resilience, a new study suggests the disaster could set off a domino effect, knocking over tipping points elsewhere in the world, too, abruptly accelerating environmental crises and causing irreparable damage to the planet.

Tipping points in the global climate system, such as collapsing ice sheets, glacier melt, forest dieback, sea level rise, and shifting monsoons, have received a lot more attention in recent years.

Each one of these switches could seriously turn up the heat on our planet, creating a 'hothouse Earth' with irreversible and catastrophic effects.

They are all connected by the global greenhouse effect, but in a climate crisis, it's uncertain in what order they will ultimately fall.

The most recent study focuses on the Amazon rainforest tipping point and some of its connections to other regional climate systems.

Using historical data from 1979 to 2019, an international team of climate researchers have drawn a link between tree loss in the Amazon and warmer temperatures in Tibet and the West Antarctic ice sheet.

Plugging this data into a model of the global climate system suggested the connection was closely synchronized with modern climate changes.

Periods of higher rainfall in the Amazon correlated with less precipitation in Tibet and West Antarctica.

Since 2008, snow cover on the Tibetan Plateau has been melting at a rapid rate similar to the Arctic.

The Plateau is sometimes known as Earth's third pole, and it plays important roles in global water storage and climate.

If the current study is correct, Tibet's loss of snow cover could be due, in part, to deforestation half a world away. The authors say the region is now operating close to a tipping point that tends to be overlooked.

"Our framework highlights that tipping elements can be linked and also the potential predictability of cascading tipping dynamics," the authors write.

The connection between Antarctica, Tibet, and the Amazon extends nearly 10,000 kilometers (6,200 miles), and it appears to be based on strong ocean currents and westerly winds.

In a review of the paper for Nature, climate scientist Valerie Livina from the United Kingdom's National Physical Laboratory agrees that the models show "strong correlations across long distances".

"This is the first time that the theory of complex networks has been applied in the context of tipping points, and the synergy of the two research areas provides an important insight into the global climate dynamics," Livina writes.

"This work opens a new area of tipping point analysis at a global scale."

Nevertheless, there is still a lot of complexity that needs to be incorporated into future models.

Deforestation in the Amazon impacts more than just Tibet and Antarctica. Previous studies suggest the climate of the Amazon, which is closely tuned by its trees, can have impacts on coral reefs in the Caribbean and reduce snowfall in the Sierra Nevada and the Cascade Mountains of North America, potentially triggering extreme drought on the west coast.

The planet's climate systems are intimately connected. It's a small world, after all.

The study was published in Nature Climate Change

Super climate action tipping points

When I saw the headline, I thought of climate tipping points. But these are tipping points in things which will reduce and reverse emissions.

With wind and solar and batteries and EVs, there were steep learning curves. Initially, the new technologies were very expensive, and volumes produced/sold were very low. In fact, they had to be subsidised at first, with wind and solar receiving high feed-in tariffs and EVs getting tax refunds or subsidies. But the learning curve processes worked. As production expanded, costs fell, which allowed sales to increase which led to further cost declines, and so it went. Today, wind and solar are the cheapest source of bulk energy. In Australia, early and vigorous support for rooftop solar led to precipitous declines costs as everybody in the system (electricians, local councils, the grid managers, panel/inverter importers) learnt how to install solar panels, connect them to the grid, etc. Today, rooftop solar is widespread and "normal" in Australia.

I have seen the argument that if we had started the subsidies for wind and solar and EVS earlier, we'd have started moving down the learning curve earlier, and we'd be closer to a zero-carbon grid. And I think that's true. What the Guardian's piece suggests is that we can repeat this process with other sources of emissions. Which makes a lot of sense (try telling that to the Right, though)

Three “super-tipping points” for climate action could trigger a cascade of decarbonisation across the global economy, according to a report.

Relatively small policy interventions on electric cars, plant-based alternatives to meat and green fertilisers would lead to unstoppable growth in those sectors, the experts said.

But the boost this would give to battery and hydrogen production would mean crucial knock-on benefits for other sectors including energy storage and aviation.

Urgent emissions cuts are needed to avoid irreversible climate breakdown and the experts say the super-tipping points are the fastest way to drive global action, offering “plausible hope” that a rapid transition to a green economy can happen in time.

The tipping points occur when a zero-carbon solution becomes more competitive than the existing high-carbon option. More sales lead to cheaper products, creating feedback loops that drive exponential growth and a rapid takeover. The report, launched at the World Economic Forum in Davos, Switzerland, said the three super-tipping points would cut emissions in sectors covering 70% of global greenhouse gas emissions.

Speedy action is vital to help avoid triggering disastrous tipping points in the climate system. Scientists said recently that global heating had driven the world to the brink of multiple tipping points with global impacts, including the collapse of Greenland’s ice cap and a key current in the north Atlantic.

“With time running out, there is a need for action to be targeted,” said Mark Meldrum, at the consultancy Systemiq, which produced the report with partners including the University of Exeter, UK. Each super-tipping point crossed raises the chance of crossing others, he said. “That could set off a cascade to steer us away from a climate catastrophe.”

The tipping point for electric vehicles is very close with sales soaring, the report says. Setting dates around the world for the end of sales of fossil-fuel powered vehicles, such as the 2030 date set for new vehicles by the UK and 2035 in China, drives further growth, the report adds.

This scale-up means the batteries used will become cheaper and these can be deployed as storage for wind and solar power, further accelerating the growth of renewables. More green energy means lower electricity bills, in turn making heat pumps even more cost-effective.

The second super-tipping point is setting mandates for green fertilisers, to replace current fertilisers, which are produced from fossil gas. Ammonia is a key ingredient and can be made from hydrogen produced by renewable energy, combined with nitrogen from the air.

Governments requiring a growing proportion of fertiliser to be green will drive a scale-up and cost reductions in the production of green hydrogen, the report says. That then supports long-distance aviation and shipping, and steel production, which will rely on hydrogen to end their carbon emissions. Mandates are being considered with India, for example, targeting 5% green fertiliser production by 2023–24 and 20% by 2027–28.

The third super-tipping point is helping alternative proteins to beat animal-based proteins on cost, while at least matching them on taste. Meat and dairy cause about 15% of global emissions. Public procurement of plant-based meat and dairy replacements by government departments, schools and hospitals could be a powerful lever, the report says.

Increasing uptake would cut the emissions from cattle and reduce the destruction of forests for pasture land. A 20% market share by 2035 would mean 400m-800m hectares of land would no longer be needed for livestock and their fodder, equivalent to 7-15% of the world’s farmland today, the report estimated. That land could then be used for the restoration of forests and wildlife, removing CO2 from the air.

Tipping points already passed within countries include electric car sales in Norway and the plunge in coal-powered electricity in the US in the past decade.

“We need to find and trigger positive socioeconomic tipping points if we are to limit the risk from damaging climate tipping points,” said Prof Tim Lenton at the University of Exeter. “This non-linear way of thinking about the climate problem gives plausible grounds for hope: the more that gets invested in socioeconomic transformation, the faster it will unfold – getting the world to net zero greenhouse gas emissions sooner.”

The same argument potentially applies to things like small modular reactors (SMRs), electric planes, green steel production, etc.  

 

Feedbacks and tipping points

 From  ....and Then There's Physics

There’s been some discussion on Twitter about feedbacks, runaways, and tipping points. The issue is that some seem to confuse these and sometimes imply that we could cross thresholds where we’ll undergo a runaway. I thought I would briefly try to explain these terms.

In the context of climate change, external factors that can lead to warming are typically called forcings. This would be things like changes to the solar flux, volcanic eruptions, and our release of greenhouse gases into the atmosphere. Feedbacks are then responses to this externally driven warming that either act to amplify, or suppress, the warming. Some of these are fast, such as water vapour and clouds, while others are slower, such as changes to vegetation or ice sheets. Some are also negative and quite strong (such as the Planck response). This means that even though the overall effect of these feedbacks is to amplify the externally-driven warming, it is limited (the negative feedbacks eventually balance the the effect of the change in forcing and the resulting positive feedbacks). For example, if we were to double atmospheric CO2, we’d expect to eventually warm by about 3oC.

A runaway, on the other hand, typically refers to what happened on Venus. Essentially, virtually all of the CO2 was released into the atmosphere, the warming was so substantial that any liquid water evaporated and was eventually lost to space, most atmospheric molecules lighter than CO2 were also lost to space, and the surface warmed by many 100s of oC. On the Earth, such a runaway is simply not possible, because most of the carbon, that can then form CO2, is locked up in the lithosphere. We can’t emit enough CO2, either through anthropogenic influences or naturally, to undergo a runaway.

Finally, a tipping point refers to us crossing some threshold where the climate system changes (tips), irreversibly, into a new state. There is the possibility of a global tipping point, but this is seen as very unlikely. However, it is possible that we could cross thresholds where some parts of the system undergo essentially irreversible changes. Examples would be melting of the West Antarctic Ice Sheet, the Greenland Ice Sheet, Amazon rain forest die-off, release of carbon from the permafrost, and the disappearance of summer Arctic sea ice.

If we were to cross any of these tipping threshold, then the changes would further amplify the warming (through either releasing additional CO2, or methane, or changing the albedo) and – in the case of the ice sheets – would lead to substantial sea level rise. There are a few things to bear in mind, though. The timescales are typically long; if we cross a tipping threshold it will still take a long time (centuries) for the full effect to manifest. Also, we don’t have a particularly good idea of where these thresholds might lie; we could already have crossed some, or might not do so unless we were to warm substantially. Additionally, there is still debate as to whether or not some of these are truly irreversible; if we could artificially draw down atmospheric CO2 would some, like Arctic summer sea ice, then reverse?

So, one does have to be slightly careful as to what one implies about tipping points and their significance. On that note, I was going to highlight a recent paper by James Annan that might initiate an interesting discussion about using tipping points in the public narrative. However, this has got long enough, so I will leave that to another post.

Update: Something I meant to stress, is that even though crossing some tipping point might lead to irreversible changes that would amplify our warming, it is still limited. There is only so much that these effects can change the albedo, and there is a limit to how much CO2, or methane, that they could release.

Update 2: If you want to read a more detailed description of the runaway greenhouse effect there is a very good Skeptical Science post by Chris Colose. There is a formal aspect to a runaway that I hadn’t appreciated, but was made aware of by MarkR’s comment. It involves a condensable greenhouse gas (such as water vapour) in equilibrium with a surface reservoir, accumulating in the atmosphere so that it eventually limits the outgoing longwavelength flux. If the incoming flux exceeds this, then energy will accumulate without there being any way to balance this. The surface will then undergo runaway warming until the entire surface reservoir of the condensable greenhouse gas has been depleted.

For water vapour, this longwavelength limit would occur at about 310W/m^2, which – given our albedo of 0.3 – is currently greater than the flux we’re receiving from the Sun. This essentially means that water vapour in the atmosphere is in a regime where it condenses, rather than accumulates. We, therefore, can’t undergo such a runaway in our current state, and no level of CO2 emissions will trigger it.

Note: none of the above suggests that we can just relax and not bother about cutting emissions.  Just because we won't have a Venusian runaway rise in temperatures does not mean we won't have steadily worsening climatic conditions as temperatures rise.  The ± 1 degree C we have had so far is already leading to record floods, droughts, hurricanes, heatwaves and bushfires.   2 degrees, which seems entirely possible given that most of the world is still not approaching the issue of global warming with enough urgency, will make all these climate extremes much worse.

Rain for the first time on Greenland summit

The National Science Foundation's Summit Greenland Environmental Observatory. Peter West / National Science Foundation

 From EcoWatch

This past weekend, researchers at the National Science Foundation's Summit Station observed rainfall at the peak of Greenland's rapidly melting ice sheet for the first time on record — an event driven by warming temperatures.

"This was the third time in less than a decade, and the latest date in the year on record, that the National Science Foundation's Summit Station had above-freezing temperatures and wet snow," the National Snow and Ice Data Center (NSIDC) said in a press release earlier this week. "There is no previous report of rainfall at this location (72.58°N 38.46°W), which reaches 3,216 meters (10,551 feet) in elevation."

Temperatures at the summit of the ice sheet rose above freezing at around 5:00 am local time on Saturday, "and the rain event began at the same time," NSIDC noted. "For the next several hours, rain fell and water droplets were seen on surfaces near the camp as reported by on-station observers."

The anomalous rainfall at the ice sheet's peak marked the start of a three-day period during which "above-freezing temperatures and rainfall were widespread to the south and west of Greenland... with exceptional readings from several remote weather stations in the area," said NSIDC. "Total rainfall on the ice sheet was 7 billion tons."

The warmer-than-usual temperatures caused significant melting of the ice sheet, with melt extent peaking at 337,000 square miles on August 14.

"Warm conditions and the late-season timing of the three-day melt event coupled with the rainfall led to both high melting and high runoff volumes to the ocean," NSIDC observed. "On August 15 2021, the surface mass lost was seven times above the mid-August average... At this point in the season, large areas of bare ice exist along much of the southwestern and northern coastal areas, with no ability to absorb the melt or rainfall. Therefore, the accumulated water on the surface flows downhill and eventually into the ocean."

This is a major tipping point for sea level rise.  The highest point of the Greenland ice sheet is 3694 m (12119 ft).  Temperatures decline at roughly 6.5 degrees C per 1000 km of elevation, so at the peak of the Greenland ice sheet, temperatures should be +- 23 degrees C cooler than at sea level.  So if temperatures at sea level in Greenland are above 23 degrees C, then the Greenland ice sheet is going to melt even at the summit.  But if the summit starts to melt,  then it will shrink, and it will warm, slowly but inexorably.  So temperatures at sea level won't need to be so high for the ice to melt.  For example, if the summit shrinks just 100 metres, its temperature will (everything else be equal) rise by 0.65 degrees C or 1.2 degrees F.  So sea level temperatures of 23.5 will be enough to melt the summit.  And so more will melt, and so the summit will shrink further, starting a doom loop which leads to the Greenland ice cap totally melting.  

This will take hundreds, perhaps thousands of years, but the point is, once it's started, it won't stop.  Over the last 50 years the Arctic has warmed 3 degrees C even though the world has warmed by 1 degree C, because of its own doom loop: ever smaller and thinner summer sea ice contributes to the heating, because the ice reflects the sun's rays but dark seawater absorbs them.   And of course, this effect is far worse in summer, and we are now routinely getting Arctic heatwaves.  If/when  the Greenland ice cap melts, the sea level will rise 6 metres (20 feet).  And that's without taking into account the melting of the Antarctic ice cap.

You can kiss goodbye to most major coastal cities.

Germany plug-in car sales more than tripled in June

EV and PHEV sales in Germany are up more than three-fold year-on-year.  They are 23% of the total market, which is way past the 5% tipping point.  It's very hard to see any future for petrol/diesel cars.   And those who think it'll take until 2040 for EVs to dominate car sales are in my opinion completely wrong--2025 looks far more likely.

From InsideEVs

In June, new passenger car registrations in Germany increased almost 25% year-over-year to 274,152, but it's still far from over 325,000 two years ago.

On the positive side, passenger plug-in car registrations increased 243% year-over-year to almost 65,000 (the second-best result ever), which represents 23.6% of the entire market.

This time, all-electric car sales not only sold at a slightly higher volume but also expanded quicker year-over-year than plug-in hybrids.

Results by type:

• BEVs: 33,420 – up 312% at 12.2% market share
• PHEVs: 31,314 – up 191% at 11.4% market share
• Total: 64,734 – up 243% at 23.6% market share

So far this year, more than 312,000 new passenger plug-in cars were registered in Germany, which is 233% more than a year ago. It's the largest plug-in market in Europe.

New registrations year-to-date:

• BEVs: 148,716 – up 236% at 10.7% market share
• PHEVs: 163,571 – up 230% at 11.8% market share
• Total: 312,287 – up 233% at 22.5% market share

Oceans likely to belch CO2 as they warm

This is another of those tipping points.  So far, a quarter of the CO2 we've generated each year has dissolved into the ocean, and the scary rise in temperatures we've seen comes from the small proportion which has remained in the atmosphere.  But what if the oceans start to release their stores of CO2 as they heat up?   

From ZME Science:

As oceans warm up due to climate change, they’ll likely start generating a lot of CO2.

Despite being the largest carbon sink active today, oceans might become net emitters under warmer climates, a new study reports. The paper reports that warmer oceans lose some of their ability to store carbon, which will accelerate the rate of CO2 regeneration in many areas of the world. This will further reduce the ocean’s ability to store carbon, the authors explain.  

“The results are telling us that warming will cause faster recycling of carbon in many areas, and that means less carbon will reach the deep ocean and get stored there,” said study coauthor Robert Anderson, an oceanographer at Columbia University’s Lamont-Doherty Earth Observatory.

Ocean water soaks up roughly 25% of our carbon dioxide emissions year after year. While this process also involves abiotic chemical and physical processes, the lion’s share of that CO2 is gobbled up by plankton through photosynthesis. But, all plankton must die eventually, and when they do, these tiny marine plants sink to the bottom of the ocean — and the carbon they ‘ate’ goes down with them. It’s estimated that plankton produces around 40 to 50 billion tons of dry, solid organic carbon each year.

Some of this organic matter (and the carbon therein) gets locked into the depths for centuries at a time, but part of it gets consumed by aerobic bacteria before sinking into oxygen-free waters, the team writes. Those bacteria then expel it as carbon dioxide, pushing it back into the atmosphere. Only about 15% of plankton-derived carbon sinks to the bottom of the sea, the authors estimate. They further report that the environmental conditions that allow bacteria to recycle carbon are spreading as water temperatures rise.

The team used data from a 2013 research cruise from Peru to Tahiti. They focused on two distinct regions: nutrient-rich, highly productive waters off South America, and the largely infertile bodies of water that form the South Pacific Gyre. Instead of using traditional sampling methods — simple devices that trap particles as they sink — the team pumped large amounts of water from different depths and isolated particles and thorium isotopes. This approach allowed them to calculate the quantity of carbon sinking at different depth intervals, they explain, and much more reliably so — the technique yielded far more data than the traditional traps.

In the oxygenated upper waters layers off South America, the team reports, oxygen gets used up very quickly. It is consumed completely at about 150 meters of depth, halting aerobic activity. Organic matter that reaches this layer (called the oxygen minimum zone, OMZ) will sink to the bottom of the ocean. In the depths, oxygen levels do increase again, and aerobic bacteria start breaking down organic matter. However, any CO2 produced down that far will take centuries to get back into the air via upwelling currents.

The OMZ thus forms a sort of protective cap over any organic matter that sinks past it, according to the team. The common wisdom of today, held that organic matter produced near the surface makes it through the OMZ, and that most CO2 regeneration takes place in the deep ocean. However, only about 15% of this matter sinks past the OMZ, the team shows.

“People did not think that much regeneration was taking place in the shallower zone,” said the study’s lead author, Frank Pavia, a graduate student at Lamont-Doherty. “The fact that it’s happening at all shows that the model totally doesn’t work in the way we thought it did.”

As mean water temperatures in the ocean increase, OMZs will spread both horizontally and vertically, covering larger areas of ocean at shallower depths, the team estimates. At the same time, higher temperatures will drive bacterial activity above the OMZs. On one hand, this would allow more organic matter to sink undegraded into the deep. However, the increased rate of CO2 regeneration near the surface will counteract this increased trapping, the team says. Whether near surface regeneration or the cap provided by the OMZ might have a stronger effect is still something we need to look into, they explain. However, this shift in OMZs is definitely not good news, as they are not at all suitable for most marine life — and this shift will affect a lot of today’s key fishing areas.

In the South Pacific Gyre, the results were less ambiguous. There is far more regeneration near the warmer surface than previously estimated in this area. The South Pacific Gyre and similar current systems in other parts of the oceans are projected to grow as the oceans warm. The gyres will divide waters into warmer layers (on the surface) and colder ones (deeper down). Because much of the CO2 regeneration will take place in the warm, shallower waters, CO2 regeneration will pick up over wide spans of ocean, the team explains. And, unlike below the nearer-shore OMZs, “there is no counterbalancing effect in the gyres,” said Anderson.

“The story with the gyres is that over wide areas of the ocean, carbon storage is going to get less efficient.” (There are four other major gyres: the north Pacific, the south and north Atlantic, and the Indian Ocean.)

Will Antarctic ice melt doom us all?

Methane clathrates burning.
Source: Wikipedia

One of the scariest tipping points is the potential melting of polar methane clathrates.  This is where methane at pressure and low temperatures is trapped into a crystal structure with water ice.  Since methane is a potent greenhouse gas, nearly 100 times as potent as CO2 over a 12 year time frame, methane released from polar clathrates could cause temperatures to rise which would in turn melt more clathrates, which would cause temperatures to rise again, and so on, in a doom loop which would raise global temperatures 4 degrees or more.  

From The Sierra Club:

For years, scientists have struggled to figure out exactly how much methane is trapped under the ice at the north and south poles and what it would mean for global temperatures if climate change melted enough ice to release that methane into the atmosphere. A new study published in Nature Communications provides the most comprehensive estimate to date: a staggering 80 to 480 gigatons. That’s a wide range, but even at the low end, it’s astonishing. For context, all the cattle and other domestic animals around the world produce an estimated .08 gigatons of methane annually. Eighty gigatons is 1,000 times that amount. 

The study, led by Jemma Wadham, a professor at the University of Bristol School of Geographical Sciences and Cabot Institute for the Environment, synthesized prior scientific research on the ice sheets. The study found that ice sheets, while seemingly inert, are intimately connected to the global carbon cycle in ways that both store and release carbon. 

In Antarctica, blinding-white ice stretches as far as the eye can see and air temperatures usually stay well below freezing. But scientists have concluded it’s likely that under the ice lies vast stores of organic carbon and methane, created by the slow decomposition of ancient vegetation and marine life that thrived during the Paleocene–Eocene Thermal Maximum (PETM), a period 55 million years ago, when Antarctica was teeming with greenery and wildlife (and much of the rest of the earth was uninhabitable). As the climate cooled, the remains of soils, plant and animal life—or marine life, in the case of marine-based ice sheets—became sediment trapped far below the ice. There, microorganisms converted some of it to methane, a potent greenhouse gas. 

“This methane is preserved because it is cold and there is enough pressure from the weight of the ice above it,” says Lev Tarasov, associate professor in the Department of Physics and Physical Oceanography at Memorial University and one of the study’s authors. But, says Tarasov, climate change is starting to shift the conditions that have held methane deposits for millions of years.

Scientists are particularly worried about the West Antarctic Ice Sheet. Where it is located, warm water imported by shifting wind patterns is washing up against the ice shelves, causing melting even in areas where the air remains cold. As the the West Antarctic Ice Sheet—and all the ice shelves—grow thinner, the possibility arises that large stores of methane will escape, taking greenhouse gas levels past the global levels that the UN Framework Convention on Climate Change (UNFCC) agreed are the maximum levels to limit warming to 2°C (3.6°F) by 2100.

But as they melt, ice sheets could also help remove carbon dioxide from the atmosphere by drawing it into the ocean. When glaciers grind against the bedrock below them, they create a fine, nutrient rich “rock flour.” As ice sheets melt, some of these nutrients are absorbed by surrounding marine ecosystems, adding vital nutrients that increase microorganism populations, which then suck up dissolved carbon dioxide from the surface level of the ocean. When the microorganisms die, they sink to the bottom of the ocean, taking the carbon dioxide with them, where it forms a carbon-rich sediment. 

Tarasov hesitated to quantify how much carbon these microorganisms could take out of the atmosphere—and how much that could mitigate the climate damage caused by the escaped methane. A question like this is one of the hardest to answer, says Tarasov, because relatively small changes in the carbon cycle can lead to huge impacts.  

“The problem with understanding the carbon cycle is it depends on the small difference between really big numbers. There is lots of carbon going from the oceans to the atmosphere, or from the atmosphere to the oceans. It just takes small little changes to shift everything around.” 

If we don't stop pumping CO2 into the atmosphere, we risk runaway global warming, from melting clathrates at the north pole (under the tundra) and the south (under the ice sheet).  Even if we are not certain of the science, we know enough to realise that it is a huge risk, and once it happens it will be irreversible.  That risk should enough incentive to make us de-carbonise our economy now, before it is too late.