(The Conversation) – As humanity continues to burn fossil fuels, the delicate balance of life on Earth is changing. That’s true of trees, many of which are growing faster as a result of increased carbon dioxide (CO₂) concentrations in our atmosphere.

But not all trees are responding in this way. In particular, eucalypts – Australia’s iconic forest trees – haven’t benefited from the increase in CO₂ as they were expected to.

Why not? Our new research, published today in Nature, shows it comes down to a below-ground battle for phosphorus, a mineral nutrient in soils that is essential for tree growth. The results suggest in some parts of the world, increased CO₂ means tiny bugs in the soil “hold onto” their phosphorus, making less available for trees.

This is alarming news, because according to current projections, global forest growth is meant to limit damage from global warming.

What our study involved

Our study used data from a Western Sydney University experiment known as “Eucalyptus Free Air CO₂ Enrichment”, or EucFACE. The experiment is located in a century-old Cumberland plain woodland in Sydney’s Hawkesbury district.

CO₂ is released into the woodland through a computer‐controlled system. Scientists then monitor the effects on trees, soils and the broader ecosystem. Over six years, CO₂ was raised to the levels expected around the year 2050 (according to the current business-as-usual emissions trajectory).

Our previous studies found the woodland trees did not show any extra growth at high CO₂ levels. We suspected the low availability of soil phosphorus was the cause, and set out to test this.

Phosphorus is crucial to the process of photosynthesis that makes trees grow. Phosphorus in soil is provided by bugs known as microbes. These micro-organisms break down dead and decaying matter, and in the process change phosphorus into a form that plants can take up with their roots.

Most Australian soils are naturally low in phosphorus, because they are derived from ancient, nutrient-depleted rocks. The same is true for most soils in tropical and subtropical regions. That makes the phosphorus service provided by microbes even more important.

We sampled phosphorus in all parts of the ecosystem, tracing its journey from the soil to the trees. We found under high-CO₂ conditions the microbes keep more of the phosphorus they produce, to aid their own metabolism. This left less available for trees to take up.

This occurred despite the trees trying to “bargain” for phosphorus by releasing extra carbon into the soil to feed the microbes.

Image by Hans from Pixabay

What’s more, trees are big “recyclers” of phosphorus – they remove half of the phosphorus from any leaf before it falls. But this was still not enough to support extra tree growth.

Why this matters

Our study is the first to show how the phosphorus cycle is affected by high CO₂ – and in particular, the role of soil microbes.

The results are important to predicting soil phosphorus availability, and plant productivity, in woodlands and forests as CO₂ levels increase in the atmosphere.

Current climate projections assume increasing CO₂ will lead to more forest growth globally. Forests are a vital carbon “sink” – that is, they draw down carbon from the atmosphere. So the increased forest growth was projected to go some way to limiting the effects of climate change.

If our results are taken into account, future warming would be higher than current projections. However, it’s important to verify our results in other locations, with other tree species. New experiments are being formed by overseas teams, including in the Amazon rainforest, to test the findings.

Importantly, our results don’t mean that forests are not a crucial sink for carbon. Forests hold a vast quantity of carbon. Avoiding deforestation and planting new forests are both valuable means of maintaining and adding to carbon stores.

Our research demonstrates the importance of considering soils when growing trees. We also hope our research stimulates further efforts to find phosphorus in ecosystems, especially in tropical rainforests where phosphorus is often greatly limited.

Kristine Crous, Senior Lecturer, Hawkesbury Institute for the Environment, Western Sydney University; Belinda Medlyn, Distinguished Professor, Ecosystem Function and Integration, Western Sydney University, and David S Ellsworth, Professor of Plant Eco-physiology, Western Sydney University

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

(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.

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.

Canada’s seemingly endless wildfires in 2023 introduced millions of people across North America to the health hazards of wildfire smoke. While Western states have contended with smoky fire seasons for years, the air quality alerts across the U.S. Midwest and Northeast this summer reached levels never seen there before.

The smoke left the air so unhealthy in Philadelphia on June 7, 2023, that the Phillies-Detroit Tigers Major League Baseball game was postponed. That same week, New York City residents hunkered down indoors for several days as a smoky haze hung over the city, turning the skies orange and exposing millions of people to the worst air quality in the world.

Smoke also drifted into the Midwest, triggering the highest air quality index levels in the Chicago area in at least 24 years, forcing the cancellation of numerous summer activities and leaving residents with raspy voices. In several states, people woke up to smoky skies day after day.

The pressing question on many people’s minds: “Is this the new normal?” From our perspective as air quality scientists, we think the answer is likely “yes.”

Global warming means more fires

The wildfire smoke of 2023 highlights an emerging air quality trend. The U.S. had seen decades of falling levels of fine particulate matter pollution, PM2.5, thanks to environmental regulations and cleaner engines, factories and power plants. But wildfires’ contribution to air pollution is increasing again, resulting in flat or rising levels of air pollution in much of the country.

Climate models predicted this reality as global temperatures rise. Hotter, drier conditions, coupled with dry grasses and underbrush that accumulated over decades of fire suppression, have made large wildfires more common. Computer simulations of the future in a warming climate show more smoky days, higher smoke concentrations, larger burned areas and higher emissions – which further fuel climate change.

While prescribed fire and forest thinning can help reduce the number and intensity of fire outbreaks, smoke exposure is still likely to increase because of the increases in burned area anticipated as a result of large-scale shifts in temperature and moisture.

In short, people will need to learn to live with wildfire smoke. It won’t be every year, but we’re likely to see summers like 2023 more often.

Fortunately, there are several tools and strategies for managing a smokier future.

Preparing for smoky days

Managing the risk of wildfire smoke starts with making smart personal choices.

Think of smoke waves like heat waves: They’re easier to face if you’re prepared and know they’re coming. That means paying attention to forecasts and having face masks, air monitors and clean-air shelters available.

Inhaling PM2.5 and the chemicals in wildfire smoke can exacerbate asthma, worsen existing respiratory and cardiac problems and leave people more susceptible to respiratory infection. People caring for individuals sensitive to smoke, such as young children and older adults, will need to plan for their needs in particular.

To prepare, read up on the risks and warning signs from public health professionals. Living with wildfire smoke may mean using air filtration devices, wearing N95 or KN95 masks on bad air days, modifying outdoor commuting patterns and activity schedules and changing household ventilation choices.

What schools and communities can do

Living with smoke will also require changes to how schools, businesses, apartment buildings and government buildings operate.

Schools can start with setting a threshold for canceling outdoor activities and making sure staff are ready to meet the needs of kids with asthma.

Building managers may need to rethink air filtration and ventilation and deploy air quality sensors. Communities will also need contingency plans for festivals and recreation venues, as well as rules for business to protect outdoor workers.

Decisions on how to deal with smoke can be complicated. For example, selecting an air purifier can be a daunting task, with over 900 products on the market. The effectiveness of different smoke management interventions are not well known and can vary depending on small implementation details, such as how a mask fits the wearer’s face, whether exterior doors and windows seal tightly and whether filters are installed properly and are replaced often enough.

Improving smoke monitoring and forecasting

The U.S. has an extensive air quality monitoring and forecasting system to help provide some early warning. It uses ground-based air quality monitors, satellite remote sensing systems to detect smoke and fires and computer systems that tie observations together with wind, chemistry and weather. These are supplemented by expert guidance from meteorologists.

However, for average people trying to make decisions about the safety of outdoor activities, the current forecasting system is wanting. This is especially true when smoke blows in from fires far away, or when rapidly changing smoke emission rates and complex wind patterns lead to conflicting forecasts and advisories.

A few key improvements would go a long way for practical decision making around wildfire smoke, like whether to delay the start of soccer practice:

• Knowledge of how fires evolve hour by hour can improve the smoke estimates going into the forecast models.

• Providing smoke forecasts at neighborhood scale can better inform individuals and cities of pending risks.

• More accurate 10-day forecasts would allow communities to plan.

• Merging seasonal weather forecasts of precipitation, humidity and winds with satellite assessments of fuel conditions could enhance emergency planning for firefighters to help anticipate which regions and periods present the highest risks of fire and smoke.

Maintaining a strong air quality monitoring network is also important. State and local government agencies have reduced the number of ground monitors by about 10% from its peak in 2001. Smoke estimates from satellites and low-cost portable sensors can help, but they work best when they can be cross-calibrated to a well-maintained network of high-accuracy monitors.

We still have a lot to learn

More effective adaptations to smoke will require more research to better understand the factors that make some people more vulnerable to harm from smoke, the effects of cumulative impacts of exposures to environmental stressors and smoke over the life span, and the efficacy and cost-effectiveness of adaptations.

For example, clean-air shelters – the equivalent to a cooling center during extreme heat – are gaining attention, but there is only limited guidance on what constitutes a clean-air shelter and where and when they would be used. A 2023 Government Accountability Office report called for better coordination to help target resources where they can be most effective.

Living with smoke is emerging as a new reality. Next-generation tools need to be both clear and resilient to the compound hazards that develop when smoke hits simultaneously with other challenges, such as extreme heat.

Charles O. Stanier, Professor of Chemical and Biochemical Engineering, University of Iowa; Gregory Carmichael, Professor of Chemical and Biochemical Engineering, University of Iowa, and Peter S. Thorne, University of Iowa Distinguished Chair, Professor of Environmental Health, University of Iowa

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

In early 2023, the Guardian published an article suggesting that more than 90% of rainforest carbon offsets are worthless. These credits are essentially a promise to protect forests and can be bought as a way to “offset” emissions elsewhere. Verra, the largest certifier of these offset credits, said the claims were “absolutely incorrect” but the story still shook confidence in the billion-dollar market. Soon after, Verra’s CEO stood down.

The claims in the Guardian article rested heavily on analysis which had been published as a preprint (before peer review). Now the research has been fully peer-reviewed and is published in the journal Science. It shows unequivocally that many projects which have sold what are known as REDD+ (reducing emissions from deforestation and degradation) credits have failed to reduce deforestation.

REDD+ projects aim to slow deforestation (for example, by supporting farmers to change their practices). They quantify the carbon saved through reducing deforestation relative to what would have happened without the project, and sell these emission reductions as credits.

Such REDD+ credits are widely used to “offset” (that is, cancel out) emissions from companies (who may use them to make claims that their operations are carbon neutral) or by people concerned about their carbon footprint. For example, if you were planning to fly from London to New York you might consider buying REDD+ credits that promise to conserve rainforest in the Congo Basin (with added benefits for forest elephants and bonobos). Offsetting your return flight would appear to cost a very affordable £16.44.

However, while previous analysis showed that some REDD+ projects have contributed to slowing deforestation and forest degradation, the central finding from the new study is that many projects have slowed deforestation much less than they have claimed and, consequently, have promised greater carbon savings than they have delivered. So that guilt-free flight to New York probably isn’t carbon neutral after all.

The finding that many REDD+ carbon credits have not delivered forest conservation is extremely worrying to anyone who cares about the future of tropical forests. We spoke to Sven Wunder, a forest economist and a co-author of the new study. He told us that: “To tackle climate change, tropical deforestation must be stopped. Forests also matter for other reasons: losing forests will result in loss of species, and will affect regional rainfall patterns. Despite the evidence that REDD+ has not been delivering additional conservation, we cannot afford to give up.”

Deforestation could simply move elsewhere

Carbon credits also face other challenges, one of the biggest being “leakage” or displacement of deforestation. Leakage may occur because the people who were cutting down the forest simply relocate to a different area. Alternatively, demand for food or timber that was fuelling deforestation in one place may be met by deforestation elsewhere – perhaps on the other side of the world. Another problem is ensuring that the forests are protected in perpetuity so that reduced deforestation represents permanent removal of carbon from the atmosphere.

Addressing these challenges is vital because selling carbon credits is an important source of finance for forest conservation. It is not too dramatic to say that unreliable REDD+ credits directly threaten forests.

However, this is an active research area and new approaches are increasingly available. Andrew Balmford is a professor of conservation science at the University of Cambridge who is actively developing methods to improve the credibility of forest carbon markets. He says the new study raises some important concerns but that more robust and transparent methods have been developed. Deploying these new methods, he told us, is “an urgent priority”.

Change is also needed to how certification operates. At present, there are incentives for verifiers to inflate estimates of the amount of deforestation that would have happened without the project, and therefore the number of credits that can be issued. Sven Wunder explains: “We need to move beyond vested interest towards independent governance employing scientifically informed, cutting-edge methods.”

Reasons to be cautious

Even if these problems can be solved, there are still reasons to be cautious about the role of carbon offsets in combating climate change. First, there is the risk that offsetting actually increases emissions because people or companies might feel more comfortable emitting carbon if they believe they can undo any damage by simply buying carbon credits. For this reason, some argue that offsets must only ever be a last resort, after all non-essential emissions have been cut (the problem being of course: who decides which emissions are essential?).

Second, keeping warming within 2°C will require most deforestation to be stopped and major reductions in fossil fuel emissions. There is a limit to which one can be used to balance out the other.

REDD+ projects mustn’t harm local farmers.

Finally, there are serious equity concerns with some forest carbon offsets. If forest conservation is achieved by stopping farmers in low-income countries from clearing land for agriculture, REDD+ may exacerbate poverty: your long haul flight would come at the expense of others being able to feed their families.

We don’t know how much it would cost to achieve genuinely additional offsets which avoid leakage and ensure equity but it is likely to be considerably more expensive than forest carbon credits currently sell for. A higher price would reduce the perception that offsetting is an easy option and should encourage more focus on reducing emissions.

So, should you buy those cheap forest carbon offsets when taking a flight? Unfortunately, there’s currently little evidence that doing so will really make your journey carbon neutral. If you want to contribute to tackling climate change, perhaps the only real option is to not take the flight.

Julia P G Jones, Professor of Conservation Science, Bangor University and Neal Hockley, Senior Lecturer in Environmental Economics & Policy, Bangor University

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

Only in the Civil War did Americans again see their country fragment and fall into hostile hands from which the pieces had to be rescued.

On this Fourth of July, we are again embroiled in a conflict on American soil, such that no municipality or region is assured of protection from an insidious enemy. Our country does not now face a human foe, not imperial Red Coats or seditious Confederates, but rather a much more powerful adversary capable of wreaking catastrophic destruction on those same cities that had been at stake in the Revolutionary War, on New York and Charleston, on Boston and Savannah. This time it is not clear that we have American generals with the foresight, skill, insight and energy to win the war. This time we could be sunk, unless the people themselves take up arms.

The enemy in this century is human-caused climate change. The menace was of our own creating, perhaps more like the slave-holding South in the Civil War than like the haughty British Empire.

The steam engine was invented in 1712, and by 1755 a copper mine in Belleville, New Jersey became the first place a steam engine began to operate in the American colonies. The current war has its seeds in the industrial practices that burgeoned during the Revolutionary War. The colonists suffered from a lack of arms, which they mostly had to liberate from British depots. Under blockade, they could only import small quantities. The few hundred artisans who could produce firearms could not make enough fast enough.

Hence, Congress established the Department of the Commissary General of Military Stores (DCGMS), which encouraged larger-scale manufacturing of arms and their repair and upkeep. This body is thought by historians to have begun the industrialization of the largely agrarian Thirteen Colonies.

Eric Sterner wrote in his review of a book on the DCGMS by Robert F. Smith, “In performing its wartime tasks, Smith also argues that the DCGMS laid the groundwork for transitioning the American manufacturing economy from small artisans and craftwork to modern eighteenth century manufacturing practices. It introduced mass production and integrated supply chains, spread innovative practices among manufacturing centers, demonstrated new ways of organizing manufacturing facilities, and created new labor practices. Bluntly, it helped usher in the American industrial revolution. Most important, perhaps, it linked a strong manufacturing economy to American ideas about securing the new country.”

Industrialization meant steam engines and iron smelting, driven by burning wood and coal, which began putting extra carbon dioxide, a heat trapping gas, into the atmosphere. The US would go on to put out 420 billion metric tons of CO2, dwarfing any other country in the world.

The global heating caused by all these extra greenhouse gases spewed out by industrial processes in turn has melted land ice and raised sea level, and has heated up oceans, making them cauldrons for mega-storms, monstrous hurricanes and gargantuan typhoons that uproot everything in their path and dump titanic reservoirs of water on coastal cities, flooding them. Hurricane Katrina a category 5, razed much of the 9th Ward in New Orleans. I saw the foundations with no houses over them anymore, since they were swept away. Hurricane Sandy in New York City. Hurricane Harvey flooded out Houston. Hurricane Maria, at some points a Category 6 (the scale only goes up to 5), flattened Puerto Rico. There have always been hurricanes and cyclones. Global heating has made them more intense, and the air more full of moisture, so that they raze where once they damaged and they flood where once they drenched.

Sea level rise threatens Savannah now just as Lt. Col. Archibald Campbell menaced it in 1778. Some 76% of buildings in Savannah are at high risk of flooding. A quarter of the buildings are close to forests that are at risk of wildfires because of extreme heat. The number of days over 96.4ºF will rise from 7 to 38 by 2050. At the moment, in August humidity reaches 73%. That plus very high temperatures could be fatal. Human beings cool off by sweating, but that doesn’t work in high heat and humidity, producing heat stroke.

Having faced reversals in the north, General Sir Henry Clinton, Lt. Col. Mark Prevost and General Charles Lord Cornwallis relocated to Charleston in 1780, which they besieged. The stubborn American defenders refused to surrender in the face of superior numbers and firepower, but when the British subjected the city to bombardment with heated balls that caused fires, they finally gave in and the nascent US lost a fighting force of 5,000 men.

Sea level rise and the risk of storm surges and flooding now threaten Charleston even more direly than did General Clinton’s inexorable advance.

The armaments in our struggle against the red coating of the earth by global heating are green energy, energy conservation, and green agriculture. We must deploy solar panels in the place of muskets, wind turbines in the place of cannons, battery storage in the place of bayonet charges. The enemy is all around us and our key cities are besieged.

For this reason, we need to make the Fourth of July a symbol of our independence from the ravages of human-caused climate change. We need laser light shows, powered by solar panels, instead of Chinese gunpowder fireworks, which produce long-lasting toxins and CO2. We need barbecued vegetables, fish and fowl rather than high-carbon beef. We need to avoid plastics. We need to cook with clean electricity produced by solar panels. We need EVs for transportation to parks and parades. A high-carbon Fourth is like a Benedict Arnold who went over to the enemy.

We must keep our morale high. This is a war that can be won. It is not too late, and will never be too late, to ameliorate the situation and avoid the worst effects of climate change. We can look forward by 2050 to a magnificent triumph for humanity. The General Cornwallis of fossil fuels will be surrounded, cut off, and made to surrender.

God bless America.

Over the past two decades, a staggering 21.8 million Americans found themselves living within 3 miles (5 kilometers) of a large wildfire. Most of those residents would have had to evacuate, and many would have been exposed to smoke and emotional trauma from the fire.

Nearly 600,000 of them were directly exposed to the fire, with their homes inside the wildfire perimeter.

Those statistics reflect how the number of people directly exposed to wildfires more than doubled from 2000 to 2019, my team’s new research shows.

But while commentators often blame the rising risk on homebuilders pushing deeper into the wildland areas, we found that the population growth in these high-risk areas explained only a small part of the increase in the number of people who were exposed to wildfires.

Instead, three-quarters of this trend was driven by intense fires growing out of control and encroaching on existing communities.

That knowledge has implications for how communities prepare to fight wildfires in the future, how they respond to population growth and whether policy changes such as increasing insurance premiums to reduce losses will be effective. It’s also a reminder of what’s at risk from human activities, such as fireworks on July 4, a day when wildfire ignitions spike.

Where wildfire exposure was highest

I am a climate scientist who studies the wildfire-climate relationship and its socioenvironmental impacts. For the new study, colleagues and I analyzed the annual boundaries of more than 15,000 large wildfires across the Lower 48 states and annual population distribution data to estimate the number of people exposed to those fires.

Not every home within a wildfire boundary burns. If you picture wildfire photos taken from a plane, fires generally burn in patches rather than as a wall of flame, and pockets of homes survive.

We found that 80% of the human exposure to wildfires – involving people living within a wildfire boundary from 2000 to 2019 – was in Western states.

California stood out in our analysis. More than 70% of Americans directly exposed to wildfires were in California, but only 15% of the area burned was there.

What climate change has to do with wildfires

Hot, dry weather pulls moisture from plants and soil, leaving dry fuel that can easily burn. On a windy day – such as California often sees during its hottest, driest months – a spark, for example from a power line, campfire or lightning, can start a wildfire that quickly spreads.

Recent research published in June 2023 shows that almost all of the increase in California’s burned area in recent decades has been due to anthropogenic climate change – meaning climate change caused by humans.

Our new research looked beyond just the area burned and asked: Where were people exposed to wildfires, and why?

We found that while the population has grown in the wildland-urban interface, where houses intermingle with forests, shrublands or grasslands, that accounted for only about one-quarter of the increase in the number of humans directly exposed to wildfires across the Lower 48 states from 2000 to 2019.

Three-quarters of that 125% increase in exposure was due to fires’ increasingly encroaching on existing communities. The total burned area increased only 38%, but the locations of intense fires near towns and cities put lives at risk.

In California, which was in drought during much of that period, several wildfire catastrophes hit communities that had existed long before 2000. Almost all these catastrophes occurred during dry, hot, windy conditions that have become increasingly frequent because of climate change.

Wildfires in the high mountains in recent decades provide another way to look at the role that rising temperatures play in increasing fire activity.

High mountain forests have few cars, homes and power lines that could spark fires, and humans have historically done little to clear brush there or fight fires that could interfere with natural fire regimes. These regions were long considered too wet and cool to regularly burn. Yet my team’s past research showed fires have been burning there at unprecedented rates in recent years, mainly because of warming and drying trends in the Western U.S.

What can communities do to lower the risk?

Wildfire risk isn’t slowing. Studies have shown that even in conservative scenarios, the amount of area that burns in Western wildfires is projected to grow in the next few decades.

How much these fires grow and how intense they become depends largely on warming trends. Reducing emissions will help slow warming, but the risk is already high. Communities will have to both adapt to more wildfires and take steps to mitigate their impacts.

Image by Ronald Plett from Pixabay

Developing community-level wildfire response plans, reducing human ignitions of wildfires and improving zoning and building codes can help prevent fires from becoming destructive. Building wildfire shelters in remote communities and ensuring resources are available to the most vulnerable people are also necessary to lessen the adverse societal impacts of wildfires.

Mojtaba Sadegh, Associate Professor of Civil Engineering, Boise State University

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