We built a network of greenhouses and rain shelters to simulate what climate change will do to soils



Mimicking the future.
Joe Fontaine, Author provided

Anna Hopkins, Edith Cowan University; Christina Birnbaum, Deakin University; Joe Fontaine, Murdoch University, and Neal Enright, Murdoch University

As most of the science community knows, the climate emergency is here now. Weather extremes such as droughts and heatwaves are increasing in frequency and intensity and are measurably exacerbated by climate change. The significant impacts of these extremes are well documented on both our native terrestrial and marine ecosystems.

Less documented is what’s happening beneath our feet. Changes below the ground are hard to measure, so most previous research has focused on what can be readily observed above the ground, such as tree deaths.

But soil is a crucial element of the climate system, being the second-largest store of carbon after the ocean. Climate change can result either in an increase in soil carbon storage (through plant growth), or in more carbon being released into the atmosphere (through plant death). Soil is also full of microbes such as fungi, bacteria and algae, and these organisms play a vital role in determining how well an ecosystem functions and how it responds to changes in climate.




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Eyes down: how setting our sights on soil could help save the climate


We have completed one of the first studies to examine the impact of drought and warmer temperatures on living organisms below the ground (known as the soil biota), in biodiverse shrublands in Western Australia, near Eneabba, about 280km north of Perth. These areas are already suffering immense climate-related stress above ground as a result of rising temperatures and longer droughts. This is making these ecosystems extremely vulnerable with many plant species facing likely extinctions in the future.

We documented significant impacts for soil biota too, with implications for the health of ecosystems in regions that are expected to experience increased drought and climate warming in the future.

We found that lower rainfall and higher temperatures are likely to affect the overall composition of soil fungal communities, and that some groups may be lost altogether.

We saw an increase in the number of fungal species that cause plant disease, whereas many common and beneficial fungi declined in response to warming and drying. These beneficial fungi contribute to many important ecosystem processes, such as boosting plant growth, and ensuring that plants get enough water and nutrients such as phosphorus.

Western Australia’s shrublands are already suffering climate stress.
Joe Fontaine, Author provided

How we did it

We built specially constructed shelters and mini-greenhouses over plots of shrubland 4x4m in size, to recreate the drier, hotter weather conditions predicted to arise between now and the end of the 21st century. This allowed us to assess how the projected future climate will affect the composition, richness and diversity of soil fungi.

Our rain shelters consisted of a roof made of gutters, widely spaced so as to intercept about 30% of the rain that fell on the plot and funnel it away.




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To study the impact of increased temperature, we enclosed separate plots on the same sites in walls made of transparent fibreglass sheeting. These worked in a similar way to a greenhouse, by reducing air flow and increasing daytime temperatures inside the shelter by 5.5℃.

We left the rain shelters and mini-greenhouses in place for four years. Then we collected soil from each plot and examined the fungi in the soil using DNA sequencing techniques.

How to engineer an artificial drought.
Joe Fontaine, Author provided

Our study revealed that it is vital to understand patterns of below-ground ecosystems as well as those we can see, if we are to accurately predict how our shrublands and other valuable ecosystems will be altered by climate change.The Conversation

Anna Hopkins, Lecturer in conservation biology and microbial ecology, Edith Cowan University; Christina Birnbaum, Honorary Fellow, Deakin University; Joe Fontaine, Lecturer, Environmental Science, Murdoch University, and Neal Enright, Professor in Plant Ecology, Murdoch University

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

On dangerous ground: land degradation is turning soils into deserts


Abbas El-Zein, University of Sydney

If any of us still has the slightest doubt that we are facing an ecological crisis on an unprecedented scale, then a new report on land degradation, released this week by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), provides yet another piece of evidence.

Land degradation can take many forms, but always entails a serious disruption of a healthy balance between five key ecosystem functions. These are: food production; fibre provision; microclimate regulation; water retention; and carbon storage.

Its impacts can be far-reaching, including loss of soil fertility, destruction of species habitat and biodiversity, soil erosion, and excessive nutrient runoff into lakes.




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The immense challenge of desertification in sub-Saharan Africa


Land degradation also has serious knock-on effects for humans, such as malnutrition, disease, forced migration, cultural damage, and even war.

At its worst, land degradation can result in the desertification or abandonment of land (or both). Protracted drought and loss of fertile land may have been contributing factors in the wars in Sudan and Syria.

According to the new report, 43% of world populations live in regions affected by land degradation. By 2050, the report estimates, 4 billion people will be living in drylands. These are defined by the United Nations as land with an “aridity ratio” of less than 0.65, meaning that the amount of water lost far outweighs the amount received in precipitation.

Such areas are highly vulnerable to food and water insecurity, especially in sub-Saharan Africa and the Middle East.

A global threat

It would be wrong to infer that land degradation is purely a problem for developing countries. Overall, land is generally more degraded in the developed world – as shown, for example, by greater declines in soil organic carbon content, a measure of soil health. However, in richer nations the rate of degradation has slowed, and people in these regions are generally less vulnerable to its effects.

It is in sub-Saharan Africa, Asia and South and Central America that the problem is growing most rapidly. But climate change, especially where droughts and forest fires are becoming more frequent, can cause land degradation even in affluent places such as California and Australia.

What’s more, a decline in the overall availability of agricultural land is bound to affect food prices globally. By 2050, the report states, humans will have transformed almost every part of the planet, apart from uninhabitable stretches such as deserts, mountains, tundra and polar regions.

Perhaps most chillingly, the report predicts that the combined effects of land degradation and climate change will have displaced between 50 million and 700 million people by 2050, potentially triggering conflict over disputed land.

Some of this migration will inevitably be across international borders – how much is impossible to tell. While the impacts on migrants are almost always devastating, the ripple effects, as we have seen recently with the Syrian war, can spread far and wide, affecting electoral outcomes, border controls and social security systems throughout the world.

Globalised causes

The two most significant direct causes of land degradation are the conversion of native vegetation into crop and grazing lands, and unsustainable land-management practices. Other factors include the effects of climate change and loss of land to urbanisation, infrastructure and mining.

However, the underlying driver of all these changes is rising per-capita demand from growing populations for protein, fibre and bioenergy. This in turn leads to more demand for land and further encroachment into areas with marginal soils.

Market deregulation, which has been a global trend since the 1980s, can lead to the destruction of sustainable land management practices in favour of monocultures, and can encourage a race to the bottom as far as environmental protection is concerned. The vast geographical distance between demand for consumer goods and the land needed to produce them – between, in other words, the cause of land degradation and its effect – makes it much harder to address the problem politically.

Sadly, the timid history of attempts to create global governance regimes over the past century – from human rights, to conflict prevention, arms control, social protections and environmental treaties – has seen more failures than successes.

On the positive side, success stories in land management are well documented: agroforestry, conservation agriculture, soil fertility management, regeneration and water conservation. In fact, the new report states that the economic case for land restoration is strong, with benefits averaging ten times the costs, even when looking at very different types of lands and communities of flora and fauna. A common feature of many of these success stories is major involvement by indigenous populations and local farmers.

And yet these achievements remain far short of the scope of the problem. Significant obstacles remain – including, according to the report, increasing demand for land, lack of awareness of the extent of land degradation, fragmented decision-making within and between countries, and increased costs of restoration as time goes by.

On the other hand, the report’s authors emphasise that a host of existing multilateral agreements, including conventions on desertification, climate change, biodiversity and wetlands, provide a strong platform for combating land degradation. However, whether these agreements will be successful in overcoming the obstacles mentioned above remains to be seen.




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If the world’s soils keep drying out that’s bad news for microbes (and people)


What can we do as citizens, especially those of us who live in cities and have little direct interaction with the land? The most obvious action is to eat less meat and, more generally, to inform ourselves about the sources and impacts of the food we buy – including its packaging, fuel and transport.

But the problem is not just about individual choices, important as these are. Underlying systemic causes need to be addressed, including deregulated international trading systems, lack of protection for local communities powerless to resist global market forces, ideologies of unfettered growth and perverse incentives for more consumption.

The ConversationArguably, what is needed is a broadening of the active scope of national politics, from an almost exclusive concern with short-term economic well-being to the making of global futures. Next time you meet your local representative, ask them what they are doing to protect the interests of your children and grandchildren. Or, even better, inform yourself, talk to others about it, form your own opinion about what should be done, then try to make it happen.

Abbas El-Zein, Professor of Environmental Engineering, University of Sydney

This article was originally published on The Conversation. Read the original article.