(The Conversation) – Tackling climate change by planting trees has an intuitive appeal. They absorb the greenhouse gas carbon dioxide from the atmosphere without using expensive technology.

The suggestion that you can plant trees to offset your carbon emissions is widespread. Many businesses, from those selling shoes to booze, now offer to plant a tree with each purchase, and more than 60 countries have signed up to the Bonn Challenge, which aims to restore degraded and deforested landscapes.

However, expanding tree cover could affect the climate in complex ways. Using models of the Earth’s atmosphere, land and oceans, we have simulated widescale future forestation. Our new study shows that this increases atmospheric carbon dioxide removal, beneficial for tackling climate change. But side-effects, including changes to other greenhouse gases and the reflectivity of the land surface, may partially oppose this.

Our findings suggest that while forestation – the restoration and expansion of forests – can play a role in tackling climate change, its potential may be smaller than previously thought.

When forestation occurs alongside other climate change mitigation strategies, such as reducing emissions of greenhouse gases, the negative side-effects have a smaller impact. So, forestation will be more effective as part of wider efforts to pursue sustainable development. Trees can help fight climate change, but relying on them alone won’t be enough.

What does the future hold?

Future climate projections suggest that to keep warming below the Paris Agreement 2°C target, greenhouse gas emissions must reach net-zero by the mid-to-late 21st century, and become net negative thereafter. As some industries, such as aviation and shipping, will be exceedingly difficult to decarbonise fully, carbon removal will be needed.

Forestation is a widely proposed strategy for carbon removal. If deployed sustainably – by planting mixtures of native trees rather than monocultures, for instance – forestation can provide other benefits including protecting biodiversity, reducing soil erosion, and improving flood protection.

We considered an “extensive forestation” strategy which expands existing forests over the course of the 21st century in line with current proposals, adding trees where they are expected to thrive while avoiding croplands.

In our models, we paired this strategy with two future climate scenarios – a “minimal effort” scenario with average global warming exceeding 4°C, and a “Paris-compatible” scenario with extensive climate mitigation efforts. We could then compare the extensive forestation outcome to simulations with the same climate but where levels of forestation followed more expected trends: the minimal effort scenario sees forest cover drop as agriculture expands, and the Paris-compatible scenario features modest increases in global forest cover.

Image by Anja from Pixabay

Up in the air

The Earth’s energy balance depends on the energy coming in from the Sun and the energy escaping back out to space. Increasing forest cover changes the Earth’s overall energy balance. Generally, changes that decrease outgoing radiation cause warming. The greenhouse effect works this way, as outgoing radiation is trapped by gases in the atmosphere.

Forestation’s ability to lower atmospheric CO₂, and therefore increase the radiation escaping to space, has been well studied. However, the amount of carbon that could feasibly be removed remains a subject of debate.

Forestation generally reduces land surface reflectivity (albedo) as darker trees replace lighter grassland. Decreases in albedo levels oppose the beneficial reduction of atmospheric CO₂, as less radiation escapes back to space. This is particularly important at higher latitudes, where trees cover land that would otherwise be covered with snow. Our scenario features forest expansion primarily in temperate and tropical regions.

Forests emit large quantities of volatile organic compounds (VOCs), with these emissions increasing with rising temperatures. VOCs react chemically in the atmosphere, affecting the concentrations of methane and ozone, which are also greenhouse gases. We find the enhanced VOC emissions from greater forest cover and temperatures increase levels of methane and, typically, ozone. This reduces the amount of radiation escaping to space, further opposing the removal of carbon.

However, the reaction products of VOCs can contribute to aerosols, which reflect incoming solar radiation and help form clouds. Increases in these aerosols with rising VOC emissions from greater forest cover result in more radiation escaping to space.

We find the net effect of changes to albedo, ozone, methane and aerosol is to reduce the amount of radiation escaping to space, cancelling out part of the benefit of reducing atmospheric CO₂. In a future where climate mitigation is not a priority, up to 30% of the benefit is cancelled out, while in a Paris-compatible future, this drops to 15%.

Cooler solutions

Tackling climate change requires efforts from all sectors. While forestation will play a role, our work shows that its benefits may not be as great as previously thought. However, these negative side-effects aren’t as impactful if we pursue other strategies, especially reducing our greenhouse gas emissions, alongside forestation.

This study hasn’t considered local temperature changes from forestation as a result of evaporative cooling, or the impact of changes to atmospheric composition caused by changes in the frequencies and severities of wildfires. Further work in these areas will complement our research.

Nevertheless, our study suggests that forestation alone is unlikely to fix our warming planet. We need to rapidly reduce our emissions while enhancing the ability of the natural world to store carbon. It is important to stress-test climate mitigation strategies in detail, because so many complex systems are at play.

James Weber, Lecturer in Atmospheric Radiation, Composition and Climate, University of Reading and James A. King, Research Associate in Climate Change Mitigation, University of Sheffield

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The Nile is one of the world’s most famous rivers. It’s also Africa’s most important freshwater system. About 300 million people live in the 11 countries it flows through. Many rely on its waters for agriculture and fishing to make a living.

The Nile’s two main tributaries, the Blue Nile and the White Nile, come together in Sudan’s capital city, Khartoum. This industrial hub has grown rapidly over the past few decades.

The Nile is not immune to the same pollutants that affect rivers all over the world. Plastic debris is of particular concern. Over time plastics break down into smaller pieces known as microplastics. These are tiny plastic particles with a maximum size of five millimetres, all the way down to the nanoscale. Recent research found that

rivers are modelled to export up to 25,000 tons of plastics from their sub-basins to seas annually. Over 80% of this amount is microplastic.

This has huge negative consequences for biodiversity and the climate. As microplastics degrade, scientists have found, they produce greenhouse gases. Airborne microplastics may influence the climate by scattering and absorbing solar and terrestrial radiation, leading to atmospheric warming or cooling depending on particle size, shape and composition. It also negatively affects animal and human health. Microplastics have been shown in laboratory studies to be toxic to animals and cells.

Much of the research about microplastics in African waters has focused on marine and coastal areas. To address this gap, I conducted a study to assess the presence of microplastics in the River Nile in Khartoum. My students and I tested for the presence of microplastics in Nile tilapia. This popular African freshwater fish species forms the basis of commercial fisheries in many African countries, including Sudan.

Photo by Islam Hassan on Unsplash

The results do not make for happy reading. In the 30 freshly caught fish we surveyed, we found a total of 567 microplastic particles. This shows that the River Nile is contaminated with microplastics that can be consumed or absorbed in various ways by the tilapia and other aquatic organisms.

Our sample

The fish used in our study were caught just after the meeting point of the two Niles, known in Arabic as Al-Mogran.

We visited the Al-Mawrada fish market in the Omdurman area, which is also alongside the Nile. All 30 specimens we bought were freshly caught.

We dissected the fish to remove their digestive tracts. The individual tracts were treated so they would digest any organic matter they contained without interfering with the analysis of microplastics. The resulting solution was subject to another extraction procedure and we then conducted physical and chemical analyses.

Every specimen had microplastics in its digestive tract.

The number ranged from as few as five to as many as 47 particles per single fish. In total we identified 567 particles. This is high compared to studies that have reported microplastics in tilapia species in other rivers and lakes. There is, as yet, no global guideline or standard for what might be an “acceptable” number.

Shape, size and colour

We detected different sizes of microplastics (0.04mm to 4.94mm), shapes (fibres, fragments, films, foams and pellets) and colours. The most common were very small (less than 1mm), fibrous – they appear slender and elongated – and coloured (dyed).

These characteristics make sense because of how fish and other aquatic organisms feed. Nile tilapia are versatile feeders: they consume a variety of organisms including phytoplankton, aquatic plants, invertebrates, detritus, bacterial films, as well as other fish and fish eggs. That puts them at a high risk of ingesting microplastics.

Nile tilapia are also more likely to consume particles that are within a similar size range as their natural prey, as well as the same shape and colour.

Smaller microplastics are especially good carriers for other pollutants such as heavy metals, resulting in additional health risks. Their small size also makes it easier for them to move into organs like the liver. Studies have found microplastics in the tissues, muscles, livers, blubber and lungs of other aquatic as well as marine mammal species.

Fibres, the most dominant shape found in our specimens, stay in the intestine for longer than other microplastic shapes. This, too, can lead to health problems for the fish. Coloured microplastics contain dyes, many of which contain toxic chemicals.

This all has serious implications for human health, as people catch and eat the fish, which introduces those microplastics and associated chemicals into their bloodstreams.

Pollution sources

Where does all this plastic originate? For starters, 65% of plastic waste in Khartoum is disposed of in open dumps. From there, it contaminates water bodies and other parts of the environment.

Image by Refaat Naiem from Pixabay

The city’s wastewater treatment system is ineffective. The three wastewater treatment plants in Khartoum state, Karary, Wd-Daffiaa and Soba, are outdated and do not meet local and international standards. That means untreated effluent from domestic, industrial and agricultural activities is another probable source of microplastic pollution.

There are also countless recreational sites along the River Nile in Khartoum. The Nile Street is the most popular in the capital city, hosting water sports, restaurants, cafes, clubs, event venues and hotels, as well as the tea ladies (women who serve hot beverages from makeshift mobile cafes along the banks of the river). However, waste disposal and collection practices are sorely lacking, so plastic litter from these leisure activities leaks into the river.

No easy fix

Tackling microplastic pollution is not easy. It will require technological advances, as well as the collective efforts of consumers, producers, governments and the scientific community.

As consumers, we need to change our behaviour around plastic products, especially single-use plastics. For example, opt for fabric shopping bags instead of plastic bags; use glass and metal containers. Recycling is also important.

Governments must enforce waste management regulations and improve waste management practices, as well as helping to improve public awareness. Strategies and policies must explicitly feature microplastics.

Scientists can not only fill the knowledge gaps around microplastics. Communicating scientific findings is crucial; so too is developing innovations to protect against microplastics and their harmful effects.

I would like to thank and acknowledge my student Hadeel Alamin, who conducted this study with me.

Dalia Saad, Researcher, School of Chemistry, University of the Witwatersrand, University of the Witwatersrand

This article is republished from The Conversation under a Creative Commons license. Read the original article.

A heat wave in Greenland and a storm in Antarctica. These kinds of individual weather “events” are increasingly being supercharged by a warming climate. But despite being short-term events they can also have a much longer-term effect on the world’s largest ice sheets, and may even lead to tipping points being crossed in the polar regions.

We have just published research looking at these sudden changes in the ice sheets and how they may impact what we know about sea level rise. One reason this is so important is that the global sea level is predicted to rise by anywhere between 28 cm and 100cm by the year 2100, according to the IPCC. This is a huge range – 70 cm extra sea-level rise would affect many millions more people.

Partly this uncertainty is because we simply don’t know whether we’ll curb our emissions or continue with business as usual. But while possible social and economic changes are at least factored in to the above numbers, the IPCC acknowledges its estimate does not take into account deeply uncertain ice-sheet processes.

Sudden accelerations

The sea is rising for two main reasons. First, the water itself is very slightly expanding as it warms, with this process responsible for about a third of the total expected sea-level rise.

Second, the world’s largest ice sheets in Antarctica and Greenland are melting or sliding into the sea. As the ice sheets and glaciers respond relatively slowly, the sea will also continue to rise for centuries.

Photo by Cassie Matias on Unsplash

Scientists have long known that there is a potential for sudden accelerations in the rate at which ice is lost from Greenland and Antarctica which could cause considerably more sea-level rise: perhaps a metre or more in a century. Once started, this would be impossible to stop.

Although there is a lot of uncertainty over how likely this is, there is some evidence that it happened about 130,000 years ago, the last time global temperatures were anything close to the present day. We cannot discount the risk.

To improve predictions of rises in sea level we therefore need a clearer understanding of the Antarctic and Greenland ice sheets. In particular, we need to review if there are weather or climate changes that we can already identify that might lead to abrupt increases in the speed of mass loss.

Weather can have long-term effects

Our new study, involving an international team of 29 ice-sheet experts and published in the journal Nature Reviews Earth & Environment, reviews evidence gained from observational data, geological records, and computer model simulations.

We found several examples from the past few decades where weather “events” – a single storm, a heatwave – have led to important long-term changes.

The ice sheets are built from millennia of snowfall that gradually compresses and starts to flow towards the ocean. The ice sheets, like any glacier, respond to changes in the atmosphere and the ocean when the ice is in contact with sea water.

These changes could take place over a matter of hours or days or they may be long-term changes from months to years or thousands of years. And processes may interact with each other on different timescales, so that a glacier may gradually thin and weaken but remain stable until an abrupt short-term event pushes it over the edge and it rapidly collapses.

Because of these different timescales, we need to coordinate collecting and using more diverse types of data and knowledge.

Historically, we thought of ice sheets as slow-moving and delayed in their response to climate change. In contrast, our research found that these huge glacial ice masses respond in far quicker and more unexpected ways as the climate warms, similarly to the frequency and intensity of hurricanes and heatwaves responding to changes with the climate.

Ground and satellite observations show that sudden heatwaves and large storms can have long-lasting effects on ice sheets. For example a heatwave in July 2023 meant at one point 67% of the Greenland ice sheet surface was melting, compared with around 20% for average July conditions. In 2022 unusually warm rain fell on the Conger ice shelf in Antarctica, causing it to disappear almost overnight.

These weather-driven events have long “tails”. Ice sheets don’t follow a simple uniform response to climate warming when they melt or slide into the sea. Instead their changes are punctuated by short-term extremes.

For example, brief periods of melting in Greenland can melt far more ice and snow than is replaced the following winter. Or the catastrophic break-up of ice shelves along the Antarctic coast can rapidly unplug much larger amounts of ice from further inland.

Failing to adequately account for this short-term variability might mean we underestimate how much ice will be lost in future.

What happens next

Scientists must prioritise research on ice-sheet variability. This means better ice-sheet and ocean monitoring systems that can capture the effects of short but extreme weather events.

This will come from new satellites as well as field data. We’ll also need better computer models of how ice sheets will respond to climate change. Fortunately there are already some promising global collaborative initiatives.

We don’t know exactly how much the global sea level is going to rise some decades in advance, but understanding more about the ice sheets will help to refine our predictions.

Edward Hanna, Professor of Climate Science and Meteorology, University of Lincoln and Ruth Mottram, Climate Scientist, National Centre for Climate Research, Danish Meteorological Institute

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Amid the escalating threats of a warming world, and with the latest annual United Nations global climate conference (COP28) behind us, there is one critical message that’s often left out of the climate change discourse. Halting overfishing is itself effective climate action.

This argument is the logical conclusion of a plethora of studies that unequivocally assert that stopping overfishing isn’t just a necessity, it’s a win-win for ocean vitality, climate robustness and the livelihoods reliant on sustainable fisheries.

The intricate relationship between climate change and ocean ecosystems was the subject of recent collaborative research — led by researchers at the University of British Columbia — that highlighted the crucial links between overfishing and climate change.

Finding the connections

Our collaborative team of international researchers applied a host of methodologies ranging from literature reviews to quantitative and quality analysis. The findings of this research illuminate eight key multifaceted impacts.

1 — Ending overfishing isn’t merely an ecological imperative but a vital climate action. Doing so would bolster marine life resilience in the face of climate shifts and reduce associate carbon emissions.

2 — Large subsidized fishing boat fleets can actually be a burden on small-scale fisheries, leaving them disproportionately vulnerable to shocks. In turn, overfishing not only depletes resources but also escalates carbon emissions, intensifying climate impacts on these fisheries and their communities, particularly women.

Additionally, the vulnerability of shellfish fisheries to climate stressors further underscores the importance of adaptive strategies tailored to local conditions.

3 — Success stories, like the recovery of European hake stocks, reveal a direct tie between stock recuperation and reduced emissions intensity from fisheries. We must champion and also learn from these successes.

4 — Ecosystem-based fisheries management reverses the “order of priorities so that management starts with ecosystem considerations rather than the maximum exploitation of several target species.”

Ecosystem-based fisheries management has considerable potential to enhance sustainable catches while fostering carbon sequestration. This is perhaps best exemplified by the successful implimentation of ecosystem-based fisheries management in the western Baltic Sea.

5 — Heavy metal pollution in the ocean — such as mercury or lead waste — intensifies the negative impacts of warming and overfishing. This pollution reinforces the need for developing multifaceted regulations based around ecosystem and ocean sustainability solutions.

6 — Overfishing exacerbates climate and biodiversity threats. Climate change contributes to less defined and predictable seasons and is causing reproductive challenges and the propagation of diseases in fish populations — among other issues.

Via Pixabay. .

Adding to these problems, overfishing itself is altering ecological dynamics, modifying habitats and opening new pathways for invasive species. These compounding crises further exacerbate the impacts of overfishing on marine ecosystems while at the same time making fish populations more vulnerable to climate change.

The above factors all combine to reduce the catch potential in any given ecosystem. In turn, fishers are forced to venture farther and deeper in the ocean to fish — increasing carbon emissions, personal risk factors to fishers and bycatch concerns.

7 — International fisheries management must play a central role in promoting biodiversity and retaining the ocean’s carbon sequestration potential. While 87 nations have signed the UN’s Biodiversity of Areas Beyond National Jurisdiction Treaty (also known as the High Seas Treaty), only one has ratified it. This treaty must be fully ratified and its effective implementation should be contingent upon the creation of marine protected areas that cover at least 30 per cent of the high seas.

8 — The ocean has huge carbon sequestration potential. Shifting from the generally accepted maximum of sustainable yield management to maximizing carbon sequestration in fisheries management could further advance climate goals.

Future regulations should allocate a percentage of the annual fish quota to maintain the carbon sequestration function of marine animals. Simply put, beyond just being food, fish stocks serve vital carbon sequestration and biodiversity services that directly benefit humanity. Future regulations should reflect this reality.

A simple goal

This joint collaborative research underscores the urgency of this issue. Ending overfishing isn’t just an ecological imperative but a linchpin for climate action. Furthermore, fisheries aren’t mere victims in these dynamics, but have real agency to play a pivotal role in either exacerbating or mitigating climate change.

An ideal governance framework would focus on managing ecosystems with considerations for their diverse benefits, based on the best evidence available. Regulation of fisheries, while controversial, is essential to not overly exploit such a valuable public resource.

As we gear up to the next COP, we would do well to remember these conclusions. Without nurturing ocean life, addressing climate change becomes an uphill battle. Sustainable fisheries management is not just an ecological necessity. It is also the cornerstone of a resilient, sustainable future.

Rashid Sumaila, Director & Professor, Fisheries Economics Research Unit, University of British Columbia

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Superstorms, abrupt climate shifts and New York City frozen in ice. That’s how the blockbuster Hollywood movie “The Day After Tomorrow” depicted an abrupt shutdown of the Atlantic Ocean’s circulation and the catastrophic consequences.

While Hollywood’s vision was over the top, the 2004 movie raised a serious question: If global warming shuts down the Atlantic Meridional Overturning Circulation, which is crucial for carrying heat from the tropics to the northern latitudes, how abrupt and severe would the climate changes be?

Twenty years after the movie’s release, we know a lot more about the Atlantic Ocean’s circulation. Instruments deployed in the ocean starting in 2004 show that the Atlantic Ocean circulation has observably slowed over the past two decades, possibly to its weakest state in almost a millennium. Studies also suggest that the circulation has reached a dangerous tipping point in the past that sent it into a precipitous, unstoppable decline, and that it could hit that tipping point again as the planet warms and glaciers and ice sheets melt.

In a new study using the latest generation of Earth’s climate models, we simulated the flow of fresh water until the ocean circulation reached that tipping point.

The results showed that the circulation could fully shut down within a century of hitting the tipping point, and that it’s headed in that direction. If that happened, average temperatures would drop by several degrees in North America, parts of Asia and Europe, and people would see severe and cascading consequences around the world.

We also discovered a physics-based early warning signal that can alert the world when the Atlantic Ocean circulation is nearing its tipping point.

The ocean’s conveyor belt

Ocean currents are driven by winds, tides and water density differences.

In the Atlantic Ocean circulation, the relatively warm and salty surface water near the equator flows toward Greenland. During its journey it crosses the Caribbean Sea, loops up into the Gulf of Mexico, and then flows along the U.S. East Coast before crossing the Atlantic.

This current, also known as the Gulf Stream, brings heat to Europe. As it flows northward and cools, the water mass becomes heavier. By the time it reaches Greenland, it starts to sink and flow southward. The sinking of water near Greenland pulls water from elsewhere in the Atlantic Ocean and the cycle repeats, like a conveyor belt.

Too much fresh water from melting glaciers and the Greenland ice sheet can dilute the saltiness of the water, preventing it from sinking, and weaken this ocean conveyor belt. A weaker conveyor belt transports less heat northward and also enables less heavy water to reach Greenland, which further weakens the conveyor belt’s strength. Once it reaches the tipping point, it shuts down quickly.

What happens to the climate at the tipping point?

The existence of a tipping point was first noticed in an overly simplified model of the Atlantic Ocean circulation in the early 1960s. Today’s more detailed climate models indicate a continued slowing of the conveyor belt’s strength under climate change. However, an abrupt shutdown of the Atlantic Ocean circulation appeared to be absent in these climate models.

Ted-Ed Video: “How do ocean currents work? – Jennifer Verduin”

This is where our study comes in. We performed an experiment with a detailed climate model to find the tipping point for an abrupt shutdown by slowly increasing the input of fresh water.

We found that once it reaches the tipping point, the conveyor belt shuts down within 100 years. The heat transport toward the north is strongly reduced, leading to abrupt climate shifts.

The result: Dangerous cold in the North

Regions that are influenced by the Gulf Stream receive substantially less heat when the circulation stops. This cools the North American and European continents by a few degrees.

The European climate is much more influenced by the Gulf Stream than other regions. In our experiment, that meant parts of the continent changed at more than 5 degrees Fahrenheit (3 degrees Celsius) per decade – far faster than today’s global warming of about 0.36 F (0.2 C) per decade. We found that parts of Norway would experience temperature drops of more than 36 F (20 C). On the other hand, regions in the Southern Hemisphere would warm by a few degrees.

These temperature changes develop over about 100 years. That might seem like a long time, but on typical climate time scales, it is abrupt.

The conveyor belt shutting down would also affect sea level and precipitation patterns, which can push other ecosystems closer to their tipping points. For example, the Amazon rainforest is vulnerable to declining precipitation. If its forest ecosystem turned to grassland, the transition would release carbon to the atmosphere and result in the loss of a valuable carbon sink, further accelerating climate change.

The Atlantic circulation has slowed significantly in the distant past. During glacial periods when ice sheets that covered large parts of the planet were melting, the influx of fresh water slowed the Atlantic circulation, triggering huge climate fluctuations.

So, when will we see this tipping point?

The big question – when will the Atlantic circulation reach a tipping point – remains unanswered. Observations don’t go back far enough to provide a clear result. While a recent study suggested that the conveyor belt is rapidly approaching its tipping point, possibly within a few years, these statistical analyses made several assumptions that give rise to uncertainty.

Instead, we were able to develop a physics-based and observable early warning signal involving the salinity transport at the southern boundary of the Atlantic Ocean. Once a threshold is reached, the tipping point is likely to follow in one to four decades.

The climate impacts from our study underline the severity of such an abrupt conveyor belt collapse. The temperature, sea level and precipitation changes will severely affect society, and the climate shifts are unstoppable on human time scales.

It might seem counterintuitive to worry about extreme cold as the planet warms, but if the main Atlantic Ocean circulation shuts down from too much meltwater pouring in, that’s the risk ahead.

This article was updated on Feb. 11, 2024, to fix a typo: The experiment found temperatures in parts of Europe changed by more than 5 F per decade.

René van Westen, Postdoctoral Researcher in Climate Physics, Utrecht University; Henk A. Dijkstra, Professor of Physics, Utrecht University, and Michael Kliphuis, Climate Model Specialist, Utrecht University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

As I began this piece on trees in forests, woods and parks, a friend asked, why in January in New England?  Why didn’t I wait until the deciduous trees were a palette of new spring green crowning the stark brown trunks and branches of winter?  The next day, January 7, nature provided the answer: a 10” snowstorm.  Trees after a winter snowstorm – their upstretched dark deciduous branches shouldered with snow and their downreaching evergreen branches pillowed with snow – are a feast for the eyes.

  “A forest is a sacred place…The medicines available in the forest are the second most valuable gift that nature offers us; the oxygen available there is the first.”  These are the words of Irish born and educated in the ancient Celtic culture of spiritual and physical respect for trees, Diana Beresford Kroeger.  This brilliant botanist went on to receive advanced degrees, culminating in a doctorate in medical biochemistry.  She affirmed that simply walking in a pine forest is a balm for the body and soul, elevating our mood, thanks to their chemical gift of pinenes aerosols released by pine trees and absorbed by our bodies. 

The healing potential of nature even stretches to those hospitalized. Patients recovering from surgery heal more quickly and need fewer pain killers if they have a hospital room with a window that looks out onto nature.  Similarly, studies of students in classrooms with a view of nature have found that they both enjoyed learning and learned more than students without a view of nature.

Suzanne Simard worked for Canada’s minister of forests doing research on the most efficient ways to re-grow forests that had been clearcut by the logging industry.  Loving forests since a child growing up in rural British Columbia, she grasped immediately that clear-cutting whole areas of a forest and applying herbicide to kill any competitor plant or tree before replanting monoculture tree seedlings was a “war on the forest.” In testing her insight, she found that clearcutting and planting single species seedling trees made no difference to speeding up the growth of the desired tree plantation and in some cases, reduced tree survival in the monoculture wood lots. 

“Healing Forest,” Digital, Dream / Mystical, 2024.

In pursuing a doctorate and subsequent years of research, Simard documented that biodiverse forests are the healthiest of forests, with trees communicating with other trees of their own species and other species by an underground fungal network linking their roots with each other. Through this network, known as the wood wide web, trees provide chemical food and medicine to keep each other as healthy as possible.  Her work has shown that “the fungal networks between roots of diverse trees carry the same chemicals as neurotransmitters in our brain,” strongly suggesting, she says, that trees have intelligence.  She has learned from Aboriginal people that “they view trees as their people, just as they view the wolves and the bears and the salmon as their relations.”  We need that back, she asserts. 

Trees teach us lessons of community and cooperation through all the seasons, writes German forester Peter Wohlleben in The Hidden Life of Trees.  He deems forests as “superorganisms,” sharing food with their own species and even nourishing their competitors.  Together they create an ecosystem that enables them to live much longer as a community than a single living tree alone, a life lesson for us humans.  Moreover, “sick trees are supported by healthy ones nearby…until they recover; and even a dead trunk is indispensable for the cycle of lifesaving as a cradle for its young.”

Trees are essential for life on earth; the older they are, the more essential they are.  They remove carbon dioxide from the air, store carbon in their tissue and soil, give back oxygen into the atmosphere and slow global temperature increases. They offer cooling shade in hardscape urban neighborhoods, buffer cold winter winds, attract birds and wildlife, purify our air, prevent soil erosion during rainstorms and filter rainwater falling through their soil.  

Without trees, we could not survive, whereas they have and could live without us.  Older than we so-called homo sapiens (“wise men”) by a thousand times, they are wiser than many humans: they do not wage war with each other nor destroy their own habitat.  They know not genocide nor ecocide.  They are our ancestral model for cooperative, non-violent and sustainable communities.

I write this to honor and thank the multitude of forest protectors across our country and for those working to restore nature to their towns and cities.

(The Conversation) – Forests are an essential part of Earth’s operating system. They reduce the buildup of heat-trapping carbon dioxide in the atmosphere from fossil fuel combustion, deforestation and land degradation by 30% each year. This slows global temperature increases and the resulting changes to the climate. In the U.S., forests take up 12% of the nation’s greenhouse gas emissions annually and store the carbon long term in trees and soils.

Mature and old-growth forests, with larger trees than younger forests, play an outsized role in accumulating carbon and keeping it out of the atmosphere. These forests are especially resistant to wildfires and other natural disturbances as the climate warms.

Most forests in the continental U.S. have been harvested multiple times. Today, just 3.9% of timberlands across the U.S., in public and private hands, are over 100 years old, and most of these areas hold relatively little carbon compared with their potential.

The Biden administration is moving to improve protection for old-growth and mature forests on federal land, which we see as a welcome step. But this involves regulatory changes that will likely take several years to complete. Meanwhile, existing forest management plans that allow logging of these important old, large trees remain in place.

As scientists who have spent decades studying forest ecosystems and the effects of climate change, we believe that it is essential to start protecting carbon storage in these forests. In our view, there is ample scientific evidence to justify an immediate moratorium on logging mature and old-growth forests on federal lands.

Endless Horizons Video: “Unlocking the Secrets of Mature and Old Growth Forests:NASA’s GEDI Instrument Reveals Global Insight”

Federal action to protect mature and old-growth forests

A week after his inauguration in 2021, President Joe Biden issued an executive order that set a goal of conserving at least 30% of U.S. lands and waters by 2030 to address what the order called “a profound climate crisis.” In 2022, Biden recognized the climate importance of mature and old-growth forests for a healthy climate and called for conserving them on federal lands.

Most recently, in December 2023, the U.S. Forest Service announced that it was evaluating the effects of amending management plans for 128 U.S. national forests to better protect mature and old-growth stands – the first time any administration has taken this kind of action.

These actions seek to make existing old-growth forests more resilient; preserve ecological benefits that they provide, such as habitat for threatened and endangered species; establish new areas where old-growth conditions can develop; and monitor the forests’ condition over time. The amended national forest management plans also would prohibit logging old-growth trees for mainly economic purposes – that is, producing timber. Harvesting trees would be permitted for other reasons, such as thinning to reduce fire severity in hot, dry regions where fires occur more frequently.

Remarkably, however, logging is hardly considered in the Forest Service’s initial analysis, although studies show that it causes greater carbon losses than wildfires and pest infestations.

In one analysis across 11 western U.S. states, researchers calculated total aboveground tree carbon loss from logging, beetle infestations and fire between 2003 and 2012 and found that logging accounted for half of it. Across the states of California, Oregon and Washington, harvest-related carbon emissions between 2001 and 2016 averaged five times the emissions from wildfires.

A 2016 study found that nationwide, between 2006 and 2010, total carbon emissions from logging were comparable to emissions from all U.S. coal plants, or to direct emissions from the entire building sector.

Logging pressure

Federal lands are used for multiple purposes, including biodiversity and water quality protection, recreation, mining, grazing and timber production. Sometimes, these uses can conflict with one another – for example, conservation and logging..

Legal mandates to manage land for multiple uses do not explicitly consider climate change, and federal agencies have not consistently factored climate change science into their plans. Early in 2023, however, the White House Council on Environmental Quality directed federal agencies to consider the effects of climate change when they propose major federal actions that significantly affect the environment.

Multiple large logging projects on public land clearly qualify as major federal actions, but many thousands of acres have been legally exempted from such analysis.

Across the western U.S., just 20% of relatively high-carbon forests, mostly on federal lands, are protected from logging and mining. A study in the lower 48 states found that 76% of mature and old-growth forests on federal lands are vulnerable to logging. Harvesting these forests would release about half of their aboveground tree carbon into the atmosphere within one or two decades.

An analysis of 152 national forests across North America found that five forests in the Pacific Northwest had the highest carbon densities, but just 10% to 20% of these lands were protected at the highest levels. The majority of national forest area that is mature and old growth is not protected from logging, and current management plans include logging of some of the largest trees still standing.

Letting old trees grow

Conserving forests is one of the most effective and lowest-cost options for managing atmospheric carbon dioxide, and mature and old-growth forests do this job most effectively. Protecting and expanding them does not require expensive or complex energy-consuming technologies, unlike some other proposed climate solutions.

Allowing mature and old-growth forests to continue growing will remove from the air and store the largest amount of atmospheric carbon in the critical decades ahead. The sooner logging of these forests ceases, the more climate protection they can provide.

Richard Birdsey, a former U.S. Forest Service carbon and climate scientist and current senior scientist at the Woodwell Climate Research Center, contributed to this article.

This is an update of an article originally published on March 2, 2023.

Beverly Law, Professor Emeritus of Global Change Biology and Terrestrial Systems Science, Oregon State University and William Moomaw, Professor Emeritus of International Environmental Policy, Tufts University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Action continues to fall far short of pledges, even as temperature and greenhouse gas records are repeatedly broken

Catherine Early

( China Dialogue ) – Countries must make far greater efforts to implement their climate strategies this decade to stand a chance of keeping global temperature rise within 1.5C (2.7F) of the pre-industrial average.

Continued delays will only increase the world’s reliance on uncertain carbon dioxide removal technologies (CDR), according to the UN Environment Programme (UNEP).

In the most recent annual assessment of progress on global climate action, the Emissions Gap Report 2023, UNEP pointed to progress since the Paris Agreement. When it was adopted in 2015, greenhouse gas emissions were projected to rise 16% by 2030. Today, that increase is projected to be 3%.

But from now emissions must fall 28% by 2030 to keep temperature rise to 3.6F (2C), or 42% to stay within 2.7F (1.5C), and countries are failing to match this need with action, UNEP found.

Photo by Andreas Felske on Unsplash

Current climate policies will result in a rise of 3C this century. The increase will be limited to 5.2F (2.9C) if countries fully implement their national climate plans (known as Nationally Determined Contributions, or NDCs).

This could be kept to 4.5F (2.5C) if plans by developing countries, which are currently conditional on obtaining financial support, are carried out – since that would result in a 9% fall in emissions.  

In UNEP’s most optimistic scenario, where all conditional NDCs and net zero pledges are met, limiting temperature rise to 3.6F (2C) could be achieved, UNEP says. This scenario is considered to give at best a 14% chance of limiting warming to 2.7F (1.5C).

Now, 97 countries have pledged to meet net zero emissions, up from 88 last year. Pledges cover 81% of the world’s greenhouse gases (GHGs). However, the authors do not consider these pledges to be credible, pointing out that none of the G20 countries are reducing emissions at a pace consistent with their net-zero targets.

National net zero plans have several flaws, according to Anne Olhoff, chief scientific editor of the report. Many are not legally binding, or fail to have clear implementation plans, and there is a lack of targets between now and the dates when governments claim to be aiming for net zero, she says.

“But most importantly, emissions are still going up in countries that have put forward zero emission pledges. There are many ways to net zero, but at some point you need to peak and reduce. And the longer you wait until you peak, the more difficult it’s likely to be to actually get to net zero,” she says.

Under the Paris Agreement, ambition in the NDCs is designed to be ramped up over time. At COP28, which begins in Dubai at the end of November, countries will debate how to build new ambition under the first Global Stocktake. This will inform the next round of NDCs that countries should submit in 2025, which will have targets for 2035.

Countries should focus on implementing existing policies this decade, rather than pledging higher targets for 2030, says Olhoff.

“Whether or not the ambition of the 2030 targets is raised or not is less important than achieving those targets. If countries find that they can also strengthen ambition for 2030, that’s an added benefit,” she says.

The more action taken this decade, the more ambitious countries can be in their new targets for 2035, and the easier it will be to achieve those targets, she points out.

The report states that high-income and high-emitting countries among the G20 should take the most ambitious and rapid action, and provide financial and technical support to developing nations.

However, it adds that low- and middle-income countries already account for more than two-thirds of global greenhouse gas emissions. Development needs in these countries need to be met with economic growth that produces low emissions, such as by reducing energy demand and prioritising clean energy, it says.

“This is an extremely large and diverse group of countries, and the opportunities for low-emissions growth depend a lot on national circumstances,” Ohloff says. Proposed reforms to international finance through multilateral development banks should improve access to finance and the ability of developing countries to attract investment. Borrowing often costs a lot more in these countries than in developed ones, she says. 

But some countries who suffer from corruption need to “get their own house in order” and improve governance to avoid this, she adds.

The role of carbon removal

The report points out that the world will also need to use carbon dioxide removal (CDR), which the authors see as having a role on three timescales.

It can already contribute to lowering net emissions, today.

In the medium term, it can contribute to tackling residual emissions from so-called hard-to-abate sectors, such as aviation and heavy industry.

And in the longer term, CDR could potentially be deployed at a large enough scale to bring about a decline in the global mean temperature. They stress that its use should be in addition to rapid decarbonisation of industry, transport, heat and power systems.

CDR refers to the direct removal of CO2 from the atmosphere and its durable storage in geological, terrestrial or ocean reservoirs, or in products. It is different to carbon capture and storage (CSS), which captures CO2 from emissions at their sources, such as a power station, and transfers it into permanent storage. While some CCS methods share features with CDR, they can never result in CO2 removal from the atmosphere.

Some CDR is already being deployed, mainly through reforestation, afforestation and forest management. However, this is very small scale, with removals estimated at 2 gigatonnes of carbon dioxide equivalent (GtCO2e) annually. Research and development into more novel technologies is increasing, with methods including sequestering carbon in soil; enhanced weathering, which speeds up the natural weathering of rocks to store CO2; and direct air capture and storage (DACC), where CO2 is extracted from the atmosphere.

There are multiple risks associated with scaling up CDR. These include competition with land for food, protection of tenure and rights, as well as public perception. In addition, the technical, economic and political requirements for large-scale deployment may not materialise in time, UNEP says. Some methods are very expensive, particularly DACC, which UNEP estimates at US$800 per tonne of CO2 removed.

Governments have tended not to specify the extent to which they plan to use CDR to achieve their emission-reduction targets, nor the residual emissions they plan to allow annually when achieving net-zero CO2 and greenhouse gas emission targets, UNEP found. Estimates of the implied levels of land-based removals in long-term strategies and net-zero pledges are 2.1-2.9 GtCO2 of removals per year by 2050, though this is based on an incomplete sample of 53 countries, the report notes.

Politicians need to coordinate the development of CDR, the report states. Dr Oliver Geden, lead author of the chapter on CDR, explains that governments need to clarify their role in national and global climate policy, and develop standards for measuring, reporting and verifying emissions reductions that can eventually be included in national GHG inventories under the UN climate change process.

Catherine Early is a freelance environmental journalist. You can find her on X @Cat_Early76.

Via China Dialogue

Republished under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY NC ND) licence

National weather analysts released their 2023 billion-dollar disasters list on Jan. 9, just as 2024 was getting off to a ferocious start. A blizzard was sweeping across across the Plains and Midwest, and the South and East faced flood risks from extreme downpours.

The U.S. set an unwelcome record for weather and climate disasters in 2023, with 28 disasters that exceeded more than US$1 billion in damage each.

While it wasn’t the most expensive year overall – the costliest years included multiple hurricane strikes – it had the highest number of billion-dollar storms, floods, droughts and fires of any year since counting began in 1980, with six more than any other year, accounting for inflation.

The year’s most expensive disaster started with an unprecedented heat wave that sat over Texas for weeks over the summer and then spread into the South and Midwest, helping fuel a destructive drought. The extreme heat and lack of rain dried up fields, forced ranchers to sell off livestock and restricted commerce on the Mississippi River, causing about US$14.5 billion in damage, according to the National Oceanic and Atmospheric Administration’s conservative estimates.

Extreme dryness in Hawaii contributed to another multi-billion-dollar disaster as it fueled devastating wildfires that destroyed Lahaina, Hawaii, in August.

Other billion-dollar disasters included Hurricane Idalia, which hit Florida in August; floods in the Northeast and California; and nearly two dozen other severe storms across the country. States in a swath from Texas to Ohio were hit by multiple billion-dollar storms.

NBC News: “New details of the devastating Lahaina wildfire that killed over 100 people”

El Niño played a role in some of these disasters, but at the root of the world’s increasingly frequent extreme heat and weather is global warming. The year 2023 was the hottest on record globally and the fifth warmest in the U.S.

I am an atmospheric scientist who studies the changing climate. Here’s a quick look at what global warming has to do with wildfires, storms and other weather and climate disasters.

Dangerous heat waves and devastating wildfires

When greenhouse gases, such as carbon dioxide from vehicles and power plants, accumulate in the atmosphere, they act like a thermal blanket that warms the planet.

These gases let in high-energy solar radiation while absorbing outgoing low-energy radiation in the form of heat from the Earth. The energy imbalance at the Earth’s surface gradually increases the surface temperature of the land and oceans.

The most direct consequence of this warming is more days with abnormally high temperatures, as large parts of the country saw in 2023.

Phoenix went 30 days with daily high temperatures at 110 F (43.3 C) or higher and recorded its highest minimum nighttime temperature, with temperatures on July 19 never falling below 97 F (36.1 C).

Although heat waves result from weather fluctuations, global warming has raised the baseline, making heat waves more frequent, more intense and longer-lasting.

That heat also fuels wildfires.

Increased evaporation removes more moisture from the ground, drying out soil, grasses and other organic material, which creates favorable conditions for wildfires. All it takes is a lightning strike or spark from a power line to start a blaze.

How global warming fuels extreme storms

As more heat is stored as energy in the atmosphere and oceans, it doesn’t just increase the temperature – it can also increase the amount of water vapor in the atmosphere.

When that water vapor condenses to liquid and falls as rain, it releases a large amount of energy. This is called latent heat, and it is the main fuel for all storm systems. When temperatures are higher and the atmosphere has more moisture, that additional energy can fuel stronger, longer-lasting storms.

Tropical storms are similarly fueled by latent heat coming from warm ocean water. That is why they only form when the sea surface temperature reaches a critical level of around 80 F (27 C).

With 90% of the excess heat from global warming being absorbed by the ocean, there has been a significant increase in the global sea surface temperature, including record-breaking levels in 2023.

Higher sea surface temperatures can lead to stronger hurricanes, longer hurricane seasons and the faster intensification of tropical storms.

Cold snaps have global warming connections, too

It might seem counterintuitive, but global warming can also contribute to cold snaps in the U.S. That’s because it alters the general circulation of Earth’s atmosphere.

The Earth’s atmosphere is constantly moving in large-scale circulation patterns in the forms of near-surface wind belts, such as the trade winds, and upper-level jet streams. These patterns are caused by the temperature difference between the polar and equatorial regions.

As the Earth warms, the polar regions are heating up more than twice as fast as the equator. This can shift weather patterns, leading to extreme events in unexpected places. Anyone who has experienced a “polar vortex event” knows how it feels when the jet stream dips southward, bringing frigid Arctic air and winter storms, despite the generally warmer winters.

In sum, a warmer world is a more violent world, with the additional heat fueling increasingly more extreme weather events.

This article, originally published Dec. 19, 2023, was updated Jan. 9, 2024, with NOAA’s disasters list.

Shuang-Ye Wu, Professor of Geology and Environmental Geosciences, University of Dayton

This article is republished from The Conversation under a Creative Commons license. Read the original article.