2016-17 has been a great year for Australian farmers, with record production, exports and profits. These records have been driven largely by good weather, in particular a wet winter in 2016, which led to exceptional yields for major crops.
Unfortunately, these good conditions go very much against the long-term trend. Recent CSIRO modelling suggests that changes in climate have reduced potential Australian wheat yields by around 27% since 1990.
In general, the drier inland parts of the cropping zone have been more heavily affected, partly because these areas are more sensitive to rainfall decline. Smaller effects have occurred in the wetter zones closer to the coast. Here less rain can have little effect on – and can even improve – crop productivity.
Farmers are reacting
However, it’s not all bad news. The study finds that Australian farmers are making great strides in adapting to climate change.
Much has been written about the fact that farm productivity in Australia has essentially flatlined since the 1990s, after several decades of consistent growth. The ABARES research suggests that changes in climate go some way towards explaining this slowdown.
After controlling for climate, there has been relatively strong productivity growth on cropping farms over the past decade. However, while farms have been improving, these gains have been offset by deteriorating conditions. The net result has been stagnant productivity.
Furthermore, there is evidence that this resurgence in productivity growth is a direct result of adaptation to the changing climate. Our study found that over the past decade cropping farms have improved productivity under dry conditions and minimised their exposure to climate variability.
This contrasts with the 1990s, when farms focused more on maximising performance in good conditions at the expense of increasing their exposure to drought.
Anecdotal evidence suggests that winter cropping farms have made a range of changes over the last decade, to better exploit soil moisture left from the summer period. The most obvious is the shift toward conservation tillage during the 2000s, where some or all of a previous crop’s residue (such as wheat stubble) is left in a field when planting the new crop.
It seems that farmers are adapting to new seasonal trends of rainfall, which for most cropping farms means less rain in winter and more in summer.
Is the Australian cropping belt moving south?
Previous research has suggested that the zone of Australia suitable for growing broadacre crops, known as the cropping belt, appears to be shifting south.
Our study found evidence to support this, with ABARES and ABS data showing increased cropping activity in the wetter southern fringe of the cropping belt in Western Australia and Victoria. At the same time, there have been declines in some more inland areas, which have been heavily affected by the climate downturn.
These shifts may be partly due to other factors – such as commodity prices and technology – but it’s likely that climate is playing a role. Similar changes have already been observed in other agricultural sectors, including the shift of wine grapes into Tasmania in response to rising temperatures.
What does this mean for the future?
At present there remains much uncertainty over future rainfall patterns. While climate models and recent experience suggest a clear direction of change, there is little agreement over the magnitude.
On the positive side, we know that farmers are successfully adapting to the changes in climate and have been for some time. However, so far at least, farmers have only been able to tread water: improving productivity just fast enough to offset the decline in climate. To remain competitive, we need to find ways to improve productivity faster, especially if current climate trends continue or worsen.
In a commentary published in Nature Climate Change today, I argue that a US withdrawal would minimise risks and maximise opportunities for the climate community. Simply put: the US and the Trump administration can do more damage inside the agreement than outside it.
There are four key, interconnected risks related to US participation in the Paris Agreement: that the US will miss its emissions target; that it will cut climate finance; that it will cause a “domino” effect among other nations; and that it will impede the UN negotiations.
Money and emissions are all that matter
The first two risks are unaffected by withdrawal. The Paris Agreement doesn’t require the US to meet its current emissions reduction pledge, or to provide further climate finance to developing countries. The agreement is procedural, rather than binding; it requires a new, tougher climate pledge every five years, but actually hitting these targets isn’t mandatory.
The same goes for international climate funding, which will be cut under the “America First” budget plan. That includes funds previously earmarked for the Green Climate Fund, which has so far raised US$10 billion in climate aid. The US was to provide US$3 billion but has donated just US$1 billion so far. The remaining money is almost certainly not coming.
The third risk is the domino effect: that US actions could inspire others to delay climate action, renege on their targets, or withdraw. But there is little evidence to suggest that the US dropping out will trigger other nations to follow suit.
The closest historical parallel is the Kyoto Protocol, which the US signed but never ratified. When President George W. Bush announced that the US would not ratify the treaty, others rallied to the protocol’s aid and pushed through the Marrakech Accords in 2001, to strengthen Kyoto’s rules.
What’s more likely to cause a domino effect is US domestic behaviour, rather than any potential withdrawal from the Paris deal. Other countries are more likely to delay or free-ride on their pledges if they see the US miss its target, revealing how weak the Paris Agreement really is.
Paris has little aside from inspiring public pressure and long-term low-carbon investment patterns. Neither pressure nor the “investment signal” is likely to work if a renegade US shows that Paris is an empty global show-and-tell regime. Investors and the public are likely to lose faith in an agreement that can visibly do nothing to constrain a climate laggard.
The fourth risk is that the US will act as a spoiler in international climate talks. This requires membership. If the US remains in the agreement it will retain a veto in the negotiations.
The negotiations are at a crucial juncture. The so-called “Paris Rulebook”, which details how exactly the agreement will be fulfilled, is being negotiated, with plans for it to be adopted in 2018.
The US could use its voice and veto to water down the rules. It might even stall and overload negotiations by demanding amendments to the Paris Agreement, as Energy Secretary Rick Perry has suggested. A US that has credibly threatened to withdraw may have even more diplomatic clout going forward.
Considered in this light, giving the former head of ExxonMobil a “seat at the table” is a terrible idea.
A US withdrawal, on the other hand, could create new opportunities, such as renewed European and Chinese leadership. In the wake of the 2016 US election, former French presidential nominee Nicholas Sarkozy raised the idea of applying a carbon tax of 1-3% on US imports. In a time of rising protectionist policies, particularly in the US, carbon border tariffs may become more politically palatable.
A US dropout would also be an ideal opportunity for a rising China to stamp its mark on an international issue. It would give both China and the European Union a chance to jump even further ahead of the US in the renewable energy markets of the future.
The EU previously showed leadership in the absence of the US to revive the Kyoto Protocol and forge ahead with renewable energy. This time Europe could do so with the support of another great power.
Such cooperation could take numerous forms. One simple way would be for the two to put forward a stronger joint climate pledge. This could be strengthened by uniting their respective carbon trading schemes and applying a common border carbon tariff.
Trade measures and an EU-China climate bloc will be far more effective than Paris ever could have been. Yet none of these possibilities is likely to become reality without the diplomatically drastic move of US withdrawal. On balance, it is clear that a US climate exit is preferable to remaining.
It is worth stressing here the difference between pulling out of the Paris Agreement and withdrawing from the UNFCCC. The latter is far more dramatic, and more likely to trigger a domino effect. It would also mean the US would no longer be legally bound to report on its emissions and actions to the international community. It would become a complete climate pariah.
A future president could easily rejoin Paris through an executive agreement. In contrast, re-ratifying the UNFCCC might require a vote in the US Senate, which has become more partisan and divided since the convention was first ratified in 1992. However, withdrawal from the UNFCCC would lessen the threat of US obstruction, as it would lose its veto in the wider negotiations and be even more politically ostracised.
Despite this, the same basic risk-opportunity calculus applies. The domino effect may be more likely, but overall a withdrawal is still preferable.
Participation is a red herring
Wanting the US to remain is a short-sighted, knee-jerk reaction. The international community should be much more worried about the real domestic actions of the US, rather than whether it is symbolically cooperating internationally.
The international community appears to be mortally afraid that the US will make the largely symbolic gesture of quitting Paris. Yet there was less concern when Trump rolled back domestic climate measures.
EU Climate Commissioner Miguel Arias Cañete recently stated that Paris allows for the continued use of fossil fuels and provides the flexibility for a “new US administration to chart its own path”.
Is this really a worthwhile message to send to the White House: that blatantly violating the purpose and spirit of the Paris Agreement is fine, as long as you are still cooperating on paper? It is disturbing that symbolism has apparently become more important than action.
Policy, not participation, needs to be the focus of criticism. Otherwise Paris will prove itself to be nothing more than a diplomatic fig leaf.
While Paris may be weak, international climate action can still be strong. The shock of Trump’s withdrawal could make international action stronger by allowing emboldened leadership to blossom elsewhere.
While it may not lead directly to impassioned critiques of climate governance, nor immediately sort the sceptics from the believers, talk of brewing storms or dried-up reservoirs now carries with it a whiff of trepidation about our collective forecasts.
Bridging the divide
Despite the growing politicisation of weather talk, weather and climate are usually understood as empirically distinct bodies of knowledge. Climate is, to quote British comedy duo Armstrong and Miller, “a long-term trend averaged over many years”, as opposed to weather, “which is what’s going on outside the window right now”.
The problem with this distinction is that climate change’s global reach and extended time scale can make it seem like it is happening somewhere else and to someone else (or, indeed, not at all). So perhaps the distinction is not useful for the cultural processes of adaptation. What might happen if we were to breach official definitions and disciplinary lines and think of the two things together?
Closing the distance between weather as event and climate as pattern can accomplish several things. Most obviously, it reminds us that there is a relationship between the two. Without weather, there would be nothing to amalgamate as climate.
While one heatwave does not equate to “climate change”, many and increasing ones give us pause to wonder. Leslie Hughes and Will Steffen are doing the data-driven work in this regard.
In other words, bringing climate and weather together can remind us that climate change is not only about abstract calculations on scales too big for our small and ultimately short-lived human forms to fathom.
Thinking about weather as part of climate underscores that we experience climate change with and on our bodies; climate change is lived by us at a very human scale, too.
The daily experience of weathering
So, what would it mean to harness the daily, mundane intrusions of weather as political? In contrast to terms like resilience (complicit with neoliberal incitements of bootstrapping) or sustainability (which suggests we get to keep something intact), weathering invites us to consider what we will lose along the way.
Weathered bodies, weathered houses, weathered cars, weathered clothes, weathered relationships, weathered dreams – these all bear scars of what has worn them down, and of what they have been asked to carry, to survive, and to hack.
Bringing this sense of lived climate change to our everyday perception is neither an easy nor comfortable thing. For one, discomfort is not a place we generally like to dwell for long. In a more political sense, though, paying attention to the weather as something in which we are intimately implicated, not just a disconnected backdrop to our human dramas, reminds us we are weather-makers too.
On a stable planet, nature provided a background against which the human drama took place; on the unstable planet we’re creating, the background becomes the highest drama.
This could be the epigraph for the Anthropocene.
Even in wealthy, climate-controlled places, weather inserts a reminder of one’s privilege, or luck, or vulnerability, or hardship, into those once mundane spaces. We may bemoan the slipping away of vacuous weather chats — “does everything have to be political?” — but perhaps noticing the weather can become an opening for everyday engagement in the politics of climate change instead.
In gender and cultural studies and the environmental humanities, rather than trying to leave weather-talk pregnant with fear, anticipation or political outrage, we are explicitly thinking with and through the weather to develop strategies for a rigorous and political response to climate change.
One way we are doing this is through a tactic or practice we call “weathering” – that is, cultivating attunement to how our own bodies, and bodies of others, experience weather. This includes how we and they manage it architecturally, technologically, professionally and socially.
We don’t all weather equally
Through the concept of “weathering”, our work forces a confrontation between large-scale climate data and embodied sociopolitical experiences that are too often treated as separate. It also underscores the politics and activism we hope this tactic can engender.
Such attentive acclimatisation reveals that, even though we’re all in the same planetary boat when it comes to global warming, we’re not all in it in the same way. This is something ecofeminists and environmental justice scholars have long known. Our work helps articulate how difference also marks our apparently banal encounters with the weather.
At a “Hacking the Anthropocence” symposium in Sydney this month, scholars, artists and activists are responding to the idea of “weathering”. The variety of experience that such a provocation reveals is astounding.
For Anne Werner’s and Genevieve Derwent’s work growing chickens on Autumn Farm and Cameron Muir’s reflections on life jackets for refugees, the weather holds a very different significance and function. Climate change is undoubtedly political – but all the more so because of these uneven individual and collective experiences of the weather.
Other kinds of bodily, socioeconomic, historical and geopolitical differences further complicate how we weather the world. When it comes to rising sea levels, or dried-up water holes, for example, racism, colonialism and gendered labour are all significant. Weathering as a concept thus asks us to think about what else, besides meteorological phenomena, one might be asked to weather.
Note that a more common meaning of “weathering” is as synonym for withstanding or enduring. Not only will different regions weather differently in a changing climate (drier, hotter in central Australia; more flooding on the US Atlantic coast; disappearing land in Pacific Islands), but people within those regions weather differently too.
Our human experiences of weather are linked to how the non-human world is weathering what we have forced it to carry. Artist Victoria Hunt will ask us to imagine with her “The Cry of Water”, while archaeologist Denis Byrne will explore the significance of seawalls, which are weathered by erosion. Human and non-human worlds weather together in a fraught and desirous intimacy.
The animal world is also constantly weathering. We know about catastrophic events such as the endangered bats that cannot cope with heat above 42℃. We’ve learned that the Great Barrier Reef is bleaching as water temperatures rise.
But what about the less-well-known water-holding frog or, indeed, ants and brine shrimp? How do they weather? At our symposium, Rebecca Giggs, Kate Wright and Emily O’Gorman (respectively) will let us know how, and suggest what we humans might learn about weathering the world differently.
These contributions invite us to explore how our experiences of the weather are highly mediated by a range of social, political and cultural forces. Anthropologist of institutions Tess Lea will investigate how bureaucracy (materialised as mountains of paperwork) orients different populations’ capacity to weather. Cli-fi expert and petrocultures scholar Stephanie LeMenager invites us to speculate on what a new kind of civic engagement might look like in this context.
Weathering directly connects human social, cultural and economic structures such as racism, colonialism and gender oppression to climate change. It insists that we think about global warming on a massive scale as always textured by acute experiences of social phenomena.
We recognise that the weight of a changing climate will not be borne equally by bodies – across geographies, economic status, or species.
So next time you curse a forgotten umbrella as the skies open up, or welcome the sun shining on your kid’s birthday party in the park, remember that when it comes to the weather, the personal is getting more and more political.
Hacking the Anthropocene II: Weathering (May 25-31) is supported by the Sydney Social Sciences and Humanities Advanced Research Centre (SSSHARC); the Australian Research Council Centre of Excellence for the History of Emotions; the Sydney Environment Institute at the University of Sydney; the Planetary Health Initiative at the University of Sydney; and the Seed Box: a MISTRA-FORMAS Environmental Humanities Collaboratory (hosted at Linkoping University, Sweden).
If we are to slow these disturbing trends and stabilise the climate at a level with which we might be able to cope, only a relatively small amount of the world’s remaining coal, oil and gas reserves can actually be used.
The majority must be left unburned in the ground, without developing vast new coal deposits such as those in the Galilee Basin.
To give ourselves just a 50% chance of staying within the 2℃ Paris target, we can burn only 38% of the world’s existing fossil fuel reserves. When this budget is apportioned among the various types of fossil fuels, coal is the big loser, because it is more emissions-intensive than other fuels. Nearly 90% of the world’s existing coal reserves must be left in the ground to stay within the 2℃ budget.
When the carbon budget is apportioned by region to maximise the economic benefit of the remaining budget, Australian coal in particular is a big loser. More than 95% of Australia’s existing coal reserves cannot be burned, and the development of new deposits, such as the Galilee Basin, is ruled out.
The health case
Exploiting coal is very harmful to human health, with serious impacts all the way through the process from mining to combustion. Recently the life-threatening “black lung” (coal workers’ pneumoconiosis) has re-emerged in Queensland, with 21 reported cases. Across Australia, the estimated costs of health damages associated with the combustion of coal amount to A$2.6 billion per year.
In India, the country to which coal from the proposed Carmichael mine would likely be exported, coal combustion already takes a heavy toll. An estimated 80,000-115,000 deaths, as well as 20 million cases of asthma, were attributed to pollutants emitted from coal-fired power stations in 2010-11. Up to 10,000 children under the age of five died because of coal pollution in 2012 alone.
Compared with the domestic coal resources in India, Carmichael coal will not reduce these health risks much at all. Galilee Basin coal is of poorer quality than that from other regions of Australia. Its estimated ash content of about 26% is double the Australian benchmark.
This is bad news for children in India or in any other country that ends up burning it.
The economic case for the Carmichael mine doesn’t stack up either. Converging global trends all point to rapidly reducing demand for coal.
The cost of renewable energy is plummeting, and efficient and increasingly affordable storage technologies are emerging. Coal demand in China is dropping as it ramps up the rollout of renewables. India is moving towards energy independence, and is eyeing its northern neighbour’s push towards renewables.
All of these trends greatly increase the risk that any new coal developments will become stranded assets. It’s little wonder that the financial sector has turned a cold shoulder to the Carmichael mine, and Galilee Basin coal development in general. Some 17 banks worldwide, including the “big four” in Australia, have ruled out any investment in the Carmichael mine.
From any perspective – climate, health, economy – the proposed mine is hard to justify. And yet the project keeps on keeping on.
So far we have had about 1℃ of global warming above the average pre-industrial climate. So how will extreme weather events change with more warming in the future? Will they become more frequent? Will they become more severe?
The Paris Agreement, brokered in 2015, committed the world’s governments to:
Holding the increase in the global average temperature to well below 2℃ above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5℃ above pre-industrial levels, recognising that this would significantly reduce the risks and impacts of climate change.
It is vital that we understand how climate extremes in Australia might change if we limit global warming to either 1.5℃ or 2℃, and what the implications might be of pursuing the more lenient target rather than the more ambitious one.
In our study we used state-of-the-art climate model simulations to examine the changing likelihood of different climate extremes under four different scenarios: a natural world without any human-caused climate change; the world of today; a 1.5℃ warmer world; and a 2℃ warmer one.
Heat extremes are here to stay
First, we looked at hot Australian summers, like the record-breaking “angry summer” of 2012-13.
Australian summer temperatures are strongly related to the El Niño-Southern Oscillation, with hot summers more likely to occur during El Niño events, and cooler ones during La Niña episodes.
In the past, a summer as hot as 2012-13 would have been very unlikely during a La Niña. But our modelling predicts that with either 1.5℃ or 2℃ of global warming, we could expect similarly angry summers to occur during both El Niño and La Niña periods.
We already know that the sea surface temperatures associated with mass bleaching of much of the Great Barrier Reef in early 2016 would have been virtually impossible without climate change. If the world continues to warm to either the 1.5℃ or 2℃ levels, very warm seas like we saw early last year would become the norm.
In fact, our research suggests that with 2℃ of global warming, the future average sea temperatures around the Great Barrier Reef would be even hotter than the extremes observed around the time of the 2016 bleaching.
Less change for heavy rains and droughts
In December 2010 Queensland was devastated by severe flooding following very heavy rainfall. Our analysis suggests that this kind of event is highly unusual, and may well continue to be so. There isn’t a clear signal for an increase or decrease in those events with ongoing climate warming.
Natural climate variability seems to play a greater role than human-driven climate change (at least below the 2℃ threshold) when it comes to influencing Australian heavy rainfall events.
The Millennium Drought across southeast Australia led to water shortages and crop failures. Drought is primarily driven by a lack of rainfall, but warmer temperatures can exacerbate drought impacts by increasing evaporation.
Our results showed that climate change is increasing the likelihood of hot and dry years like we saw in 2006 across southeast Australia. At 1.5℃ and 2℃ of global warming these events would probably be more frequent than they are in today’s world.
Not a lost cause
It is clear that Australia is going to suffer from more frequent and more intense climate extremes as the world warms towards (and very likely beyond) the levels described in the Paris Agreement.
If we miss these targets, the warming will continue and the extremes we experience in Australia are going to be even worse.
With either 1.5℃ or 2℃ global warming, we will see more extremely hot summers across Australia, more frequent marine heatwaves of the kind that can cause bleaching of the Great Barrier Reef, and probably more frequent drought conditions too.
The more warming we experience, the worse the impacts will be. The solution is clear. To limit global warming, the world’s nations need to reduce their greenhouse gas emissions – fast.
Many of Australia’s most carbon-intensive companies are either not participating in the federal government’s flagship Emissions Reduction Fund (ERF), or are adopting a wait-and-see approach, according to our survey of senior executives.
The ERF, introduced in 2014 after the repeal of the carbon tax, is the central component in the government’s policy to reduce greenhouse emissions. Companies can bid for money from an overall fund of A$2.55 billion, to invest in low-carbon technologies and initiatives. Participation is voluntary.
Five ERF auctions have been held, awarding A$2.23 billion so far. However, participation by high-emitting companies has been persistently low.
Some of the funded projects are likely to deliver useful emissions cuts in areas such as forestry, landfill and waste management. But the scheme is yet to reduce emissions reductions in key sectors of the economy such as industry and electricity generation. Our survey underlines concerns that the scheme is not attracting the biggest emitters.
Asking the questions
Our research, titled the Australian Emission Reduction Fund Survey and produced in collaboration with the Carbon Market Institute, was conducted in two rounds.
First, in 2015, we surveyed executives from high-emitting companies in sectors including mining, manufacturing, energy and transport. Then, in 2016, we surveyed executives from firms that had successfully registered carbon-reduction projects under the ERF. Survey respondents represented a broad range of positions, including managing directors, general managers, senior carbon advisers, heads of environmental markets and strategy, and chief executives.
The first-round survey, which was conducted before the first ERF auction and featured 68 participants, showed that 58% of companies planned to “wait and see” before engaging with the ERF. Another 34% said they did not intend to participate in the scheme at all.
One of the main reasons given for non-participation was the fact that the scheme is run as a reverse auction with no guarantee that bids will be successful. This makes it difficult to invest with certainty in the staffing and administration costs of running carbon-reduction projects. One participant told us:
…administrative costs do not make the ERF cost-effective for the scale of abatement opportunities available.
Respondents also told us that there was a lack of guidance on how to understand and participate in the ERF, and uncertainty over the rules of the safeguard mechanism that is meant to help drive demand for carbon credits.
Another issue that most participants highlighted is the inability to make a business case internally and to secure a relatively high price for emissions reductions. One manager emphasised:
Clearly a high price would assist in driving participation, but at the moment the package is not commercially attractive.
Furthermore, some respondents expressed concern over the perceived lack of a wide range of approved methods for cutting carbon. And almost all participants were concerned by policy uncertainty, with one saying:
…there is currently a lack of business certainty regarding carbon policy in the mid to long term.
The results of our second-round survey in 2016, featuring 33 participants from companies that have registered ERF projects, suggested that the financial risk for investors in ERF projects has reduced, having been awarded secure government contracts for delivering carbon reductions. Nevertheless, respondents highlighted a range of concerns about the scheme’s effectiveness.
All respondents highlighted the uncertainty of further funding after the initial A$2.55 billion allocation is exhausted. One participant suggested that the government’s forthcoming climate policy review, to be released this year, should specify exactly how much money the ERF will make available in the future.
Moreover, many respondents expressed doubts that contracts awarded in the ERF’s first four auctions will be completed. This has arisen partly because of a perceived lack of adequate measures to resolve potential disputes between project proponents and land holders. As one respondent told us:
The extent to which landholders understand the legal risks associated with projects is unclear.
Participants also presume that the policy’s safeguard mechanism lacks tight enough “baselines” – the emissions limits beyond which high emitters are required to buy carbon credits. Tough baselines would generate the necessary certainty of a future market, as one respondent explained:
The extent of uncertainty will also be affected by whether the safeguard mechanism is strengthened by reducing baselines, and therefore increasing the need to purchase offsets.
At the Paris climate summit in 2015, Australia pledged to cut carbon emissions by 26-28% below 2005 levels by 2030. But if the government’s flagship emissions-reductions policy is failing to involve the highest-emitting companies, that target begins to look very onerous indeed.
With the government’s major climate change policy review now underway, it is time for the government, other political parties and high-emitting companies to work together to design a climate policy that is economically efficient and environmentally effective. There is no time to “wait and see” when it comes to combating carbon emissions.
A new global analysis of the distribution of forests and woodlands has “found” 467 million hectares of previously unreported forest – an area equivalent to 60% of the size of Australia.
The discovery increases the known amount of global forest cover by around 9%, and will significantly boost estimates of how much carbon is stored in plants worldwide.
The new forests were found by surveying “drylands” – so called because they receive much less water in precipitation than they lose through evaporation and plant transpiration. As we and our colleagues report today in the journal Science, these drylands contain 45% more forest than has been found in previous surveys.
We found new dryland forest on all inhabited continents, but mainly in sub-Saharan Africa, around the Mediterranean, central India, coastal Australia, western South America, northeastern Brazil, northern Colombia and Venezuela, and northern parts of the boreal forests in Canada and Russia. In Africa, our study has doubled the amount of known dryland forest.
With current satellite imagery and mapping techniques, it might seem amazing that these forests have stayed hidden in plain sight for so long. But this type of forest was previously difficult to measure globally, because of the relatively low density of trees.
What’s more, previous surveys were based on older, low-resolution satellite images that did not include ground validation. In contrast, our study used higher-resolution satellite imagery available through Google Earth Engine – including images of more than 210,000 dryland sites – and used a simple visual interpretation of tree number and density. A sample of these sites were compared with field information to assess accuracy.
Given that drylands – which make up about 40% of Earth’s land surface – have more capacity to support trees and forest than we previously realised, we have a unique chance to combat climate change by conserving these previously unappreciated forests.
Drylands contain some of the most threatened, yet disregarded, ecosystems, many of which face pressure from climate change and human activity. Climate change will cause many of these regions to become hotter and even drier, while human expansion could degrade these landscapes yet further. Climate models suggest that dryland biomes could expand by 11-23% by the end of the this century, meaning they could cover more than half of Earth’s land surface.
Considering the potential of dryland forests to stave off desertification and to fight climate change by storing carbon, it will be crucial to keep monitoring the health of these forests, now that we know they are there.
Climate policy boost
The discovery will dramatically improve the accuracy of models used to calculate how much carbon is stored in Earth’s landscapes. This in turn will help calculate the carbon budgets by which countries can measure their progress towards the targets set out in the Kyoto Protocol and its successor, the Paris Agreement.
Our study increases the estimates of total global forest carbon stocks by anywhere between 15 gigatonnes and 158 gigatonnes of carbon – an increase of between 2% and 20%.
This study provides more accurate baseline information on the current status of carbon sinks, on which future carbon and climate modelling can be based. This will reduce errors for modelling of dryland regions worldwide. Our discovery also highlights the importance of conservation and forest growth in these areas.
The authors acknowledge the input of Jean-François Bastin and Mark Grant in the writing of this article. The research was carried out by researchers from 14 organisations around the world, as part of the UN Food and Agriculture Organization’s Global Forest Survey.