nature based solutions

26 10 2023

Manager adaptation, carbon budget, ecosystems, nature based solutions, ocean, sea levels, wetlands

Authors: Kerrylee Rogers, Associate Professor, University of Wollongong; Jeffrey Kelleway, Postdoctoral Research Fellow in Environmental Sciences, Macquarie University, and Neil Saintilan, Head, Department of Environmental Science, Macquarie University

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

Coastal wetlands don’t cover much global area but they punch well above their carbon weight by sequestering the most atmospheric carbon dioxide of all natural ecosystems.

Termed “blue carbon ecosystems” by virtue of their connection to the sea, the salty, oxygen-depleted soils in which wetlands grow are ideal for burying and storing organic carbon.

In our research, published in Nature, we found that carbon storage by coastal wetlands is linked to sea-level rise. Our findings suggest as sea levels rise, these wetlands can help mitigate climate change.

Sea-level rise benefits coastal wetlands

We looked at how changing sea levels over the past few millennia has affected coastal wetlands (mostly mangroves and saltmarshes). We found they adapt to rising sea levels by increasing the height of their soil layers, capturing mineral sediment and accumulating dense root material. Much of this is carbon-rich material, which means rising sea levels prompt the wetlands to store even more carbon.

We investigated how saltmarshes have responded to variations in “relative sea level” over the past few millennia. (Relative sea level is the position of the water’s edge in relation to the land rather than the total volume of water within the ocean, which is called the eustatic sea level.)

What does past sea-level rise tell us?

Global variation in the rate of sea-level rise over the past 6,000 years is largely related to the proximity of coastlines to ice sheets that extended over high northern latitudes during the last glacial period, some 26,000 years ago.

As ice sheets melted, northern continents slowly adjusted elevation in relation to the ocean due to flexure of the Earth’s mantle.

Karaaf Wetlands in Victoria, Australia. Boobook48/flickr, CC BY-NC-SA

For much of North America and Europe, this has resulted in a gradual rise in relative sea level over the past few thousand years. By contrast, the southern continents of Australia, South America and Africa were less affected by glacial ice sheets, and sea-level history on these coastlines more closely reflects ocean surface “eustatic” trends, which stabilised over this period.

Our analysis of carbon stored in more than 300 saltmarshes across six continents showed that coastlines subject to consistent relative sea-level rise over the past 6,000 years had, on average, two to four times more carbon in the upper 20cm of sediment, and five to nine times more carbon in the lower 50-100cm of sediment, compared with saltmarshes on coastlines where sea level was more stable over the same period.

In other words, on coastlines where sea level is rising, organic carbon is more efficiently buried as the wetland grows and carbon is stored safely below the surface.

Give wetlands more space

We propose that the difference in saltmarsh carbon storage in wetlands of the southern hemisphere and the North Atlantic is related to “accommodation space”: the space available for a wetland to store mineral and organic sediments.

Coastal wetlands live within the upper portion of the intertidal zone, roughly between mean sea level and the upper limit of high tide.

These tidal boundaries define where coastal wetlands can store mineral and organic material. As mineral and organic material accumulates within this zone it creates layers, raising the ground of the wetlands.

The coastal wetlands of Broome, Western Australia. Shutterstock

New accommodation space for storage of carbon is therefore created when the sea is rising, as has happened on many shorelines of the North Atlantic Ocean over the past 6,000 years.

To confirm this theory we analysed changes in carbon storage within a unique wetland that has experienced rapid relative sea-level rise over the past 30 years.

When underground mine supports were removed from a coal mine under Lake Macquarie in southeastern Australia in the 1980s, the shoreline subsided a metre in a matter of months, causing a relative rise in sea level.

Following this the rate of mineral accumulation doubled, and the rate of organic accumulation increased fourfold, with much of the organic material being carbon. The result suggests that sea-level rise over the coming decades might transform our relatively low-carbon southern hemisphere marshes into carbon sequestration hot-spots.

How to help coastal wetlands

The coastlines of Africa, Australia, China and South America, where stable sea levels over the past few millennia have constrained accommodation space, contain about half of the world’s saltmarshes.

Saltmarsh on the shores of Westernport Bay in Victoria. Author provided

A doubling of carbon sequestration in these wetlands, we’ve estimated, could remove an extra 5 million tonnes of CO₂ from the atmosphere per year. However, this potential benefit is compromised by the ongoing clearance and reclamation of these wetlands.

Preserving coastal wetlands is critical. Some coastal areas around the world have been cut off from tides to lessen floods, but restoring this connection will promote coastal wetlands – which also reduce the effects of floods – and carbon capture, as well as increase biodiversity and fisheries production.

In some cases, planning for future wetland expansion will mean restricting coastal developments, however these decisions will provide returns in terms of avoided nuisance flooding as the sea rises.

Finally, the increased carbon storage will help mitigate climate change. Wetlands store flood water, buffer the coast from storms, cycle nutrients through the ecosystem and provided vital sea and land habitat. They are precious, and worth protecting.

The authors would like to acknowledge the contribution of their colleagues, Janine Adams, Lisa Schile-Beers and Colin Woodroffe.

01 10 2023

Sonny adaptation, agriculture, biodiversity, carbon budget, disruptive technology, emissions trading scheme, impacts, indigenous, justice, maladaptation, mitigation, nature based solutions, Opportunities, policy, politics, transition

Mycorrhizal fungi growing with a plant root by Yoshihiro Kobae

09 06 2023

Manager agriculture, biodiversity, carbon budget, ecosystems, land use, nature based solutions, News

Image: Mycorrhizal fungi growing with a plant root Dr Yoshihiro Kobae.

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

Authors: Adam Frew, Lecturer and ARC DECRA Fellow, Western Sydney University; Carlos Aguilar-Trigueros, Postdoctoral fellow, Western Sydney University; Jeff Powell, Professor and ARC Future Fellow, Western Sydney University, and Natascha Weinberger, Postdoctoral Research Fellow, Western Sydney University

Beneath our feet, remarkable networks of fungal filaments stretch out in all directions. These mycorrhizal fungi live in partnership with plants, offering nutrients, water and protection from pests in exchange for carbon-rich sugars.

Now, new research shows this single group of fungi may quietly be playing a bigger role in storing carbon than we thought.

How much bigger? These microscopic filaments take up the equivalent of more than a third (36%) of the world’s annual carbon emissions from fossil fuels – every year.

As we search for ways to slow or stop the climate crisis, we often look to familiar solutions: cutting fossil fuel use, switching to renewables and restoring forests. This research shows we need to look down too, into our soils.

This shows how mycorrhizal fungi (fine white filaments) connect to plant root systems (yellow) and out into the soil. Scivit/Wikipedia

This fungi-plant partnership is 400 million years old

Mycorrhizal fungi are hard to spot, but their effects are startling. They thread networks of microscopic filaments through the soil and into the roots of almost every plant on earth.

But this is no hostile takeover. They’ve been partnering with plants for more than 400 million years. The length of these complex relationships has given them a vital role in our ecosystems.

Sometimes fungi take more than they give. But often, these are relationships of mutual benefit. Through their network, the fungi transport essential nutrients and water to plants, and can even boost their resistance to pests and disease.

In return, plants pump sugars and fat made by photosynthesis in their leaves down through their roots to the fungi. These compounds are rich in carbon, taken from the atmosphere.

How do these fungi fit into the carbon cycle?

On land, the natural carbon cycle involves a delicate balance. Plants take CO₂ from the atmosphere through photosynthesis, while other organisms emit it back into the atmosphere.

Carbon is captured by plants through photosynthesis, some of this carbon then goes into the networks of mycorrhizal fungi. These fungi also will release some of this carbon as CO₂ and as compounds into the soil. Adam Frew/Author provided using BioRender

Now we know the carbon transfer from plants to mycorrhizal fungi isn’t a side note – it’s a substantial part of this equation.

By analysing almost 200 datasets, the researchers estimate the world’s plants are transferring a staggering 3.58 billion tonnes of carbon per year to this underground network. That’s the same as 13.12 billion tonnes of CO₂ – more than a third of the world’s 36.3 billion tonnes of CO₂ emitted yearly by burning fossil fuels.

To be clear, fungal carbon doesn’t present a climate solution by itself. It’s a missing piece in the carbon cycle puzzle.

We still have big gaps in data from particular ecosystems and geographic regions. For instance, this study didn’t have any data of this kind from Australia or Southeast Asia – because it doesn’t yet exist.

Microscope image of plant roots that have been stained to show the mycorrhizal fungal inside the root of a plant. — This image shows mycorrhizal fungi (blue) growing inside plant roots, where they obtain carbon and provide plants with access to resources such as nutrients. Adam Frew

What does this mean for the climate?

We already know mycorrhizal fungi help soils retain carbon by releasing specific chemical compounds. These compounds contain carbon and nitrogen. Once in the soil, these compounds can be used by other soil microorganisms, such as bacteria. When this happens it helps to form a highly stable soil carbon store that is more resistant to breakdown, and this store can accumulate more than four times faster in the presence of mycorrhizal fungi.

When these fungi die, they leave behind “necromass” – a complex scaffold of dead organic material which can be stored in soil, and often inside clumps of soil particles. The carbon inside these clumps can stay in the soil for close to a decade without being released back to the atmosphere.

In fact, other studies suggest this fungal necromass might contribute more to the carbon content of soil than living fungi.

But these fungi also naturally cause carbon to escape back to the atmosphere by decomposing organic matter or changing water and nutrient availability, which influences how other organisms decompose. Mycorrhizal fungi also release some carbon back into the atmosphere, though the rate this happens depends on many factors.

What does this mean for climate change? While atmospheric CO₂ concentrations keep rising, it doesn’t necessarily mean fungi are storing more of it. Recent research in an Australian woodland found higher atmospheric CO₂ did see more carbon sent below the ground. But this carbon wasn’t stored for long periods.

To date, mycorrhizal fungi have been poorly represented in global carbon cycle models. They aren’t often considered when assessing which species are at risk of extinction or promoting successful restorations.

We need more research to better understand the role of mycorrhizal fungi in the carbon cycle across different ecosystems, including in agriculture. Dylan de Jonge/Unsplash

Protecting our fungal networks

When we cut down forests or clear land, we not only disrupt life above the ground, but underground as well. We need to safeguard these hidden fungal networks which give our plants resilience – and play a key role in the carbon cycle.

As we better understand how these fungi work and what we’re doing to them, we can also develop farming methods which better preserve them and their carbon.

As global and Australian initiatives continue to map the diversity of mycorrhizal fungi, scientists are working to understand what shapes these communities and their roles.

We’ve long overlooked these vital lifeforms. But as we learn more about how fungi and plants cooperate and store carbon, it’s well past time for that to change.

25 04 2023

Manager adaptation, biodiversity, indigenous, land use, mitigation, nature based solutions, policy, regeneration, rivers, sea levels, wetlands adaptation, planning

We can’t just sit around and wait to see what will happen next. We need positive action.

I’ve read a lot of Climate Adaptation Plans and Strategies over the past the last few years, but He Toka Tū Moana Mō Maketū (Maketū Climate Change Adaptation Plan) is hand-down the best. It’s clearly laid out, outlines the community’s priorities, and can readily serve as a template to help every community around Aoteara develop their own Climate Adaptation Plans. Most important of all:

It’s iwi led, community driven, it’s a plan that’s been decided by those who live here. – Elva Conroy, Kaitohotohu / Facilitator (Video; to listen Watch on Youtube)

Winner of the 2023 Supreme Planning Awards, the Maketū Climate Change Adaptation Plan was developed by Ngāti Pikiao Environmental Society, Te Rūnanga o Ngāti Whakaue ki Maketū , Whakaue Marae Trustees, and Conroy and Donald Consultants.

In the words of the Maketu Iwi Collective, ‘we will be resilient like the anchor stone Takaparore – strong and steadfast against the elements and tides of change and uncertainty. Regardless of what happens as a result of a changing environment, we will remain standing’. – New Zealand Planning Institute, April 2023.

Remnants of sea ice West Greenland . Image: Sonny Whitelaw

15 12 2022

Manager effects, flood, impacts, indigenous, justice, nature based solutions, News, permafrost, phenology, risk, wetlands biodiversity, Indigenous rights, methane, ocean currents, sea level rise, tipping points

Rainier, seasons shifting, with broad disturbances for people, ecosystems and wildlife

Reprinted with permission from The Conversation

Matthew L. Druckenmiller, University of Colorado Boulder; Rick Thoman, University of Alaska Fairbanks, and Twila Moon, University of Colorado Boulder

In the Arctic, the freedom to travel, hunt and make day-to-day decisions is profoundly tied to cold and frozen conditions for much of the year. These conditions are rapidly changing as the Arctic warms.

The Arctic is now seeing more rainfall when historically it would be snowing. Sea ice that once protected coastlines from erosion during fall storms is forming later. And thinner river and lake ice is making travel by snowmobile increasingly life-threatening.

Ship traffic in the Arctic is also increasing, bringing new risks to fragile ecosystems, and the Greenland ice sheet is continuing to send freshwater and ice into the ocean, raising global sea level

In the annual Arctic Report Card, released Dec. 13, 2022, we brought together 144 other Arctic scientists from 11 countries to examine the current state of the Arctic system.

Some of the Arctic headlines of 2022 discussed in the Arctic Report Card.
NOAA Climate.gov

The Arctic is getting wetter and rainier

We found that Arctic precipitation is on the rise across all seasons, and these seasons are shifting.

Much of this new precipitation is now falling as rain, sometimes during winter and traditionally frozen times of the year. This disrupts daily life for humans, wildlife and plants.

Roads become dangerously icy more often, and communities face greater risk of river flooding events. For Indigenous reindeer herding communities, winter rain can create an impenetrable ice layer that prevents their reindeer from accessing vegetation beneath the snow.

Map shows significant increases in precipitation across the Arctic in both winter and fall. — NOAA Climate.gov

Arctic-wide, this shift toward wetter conditions can disrupt the lives of animals and plants that have evolved for dry and cold conditions, potentially altering Arctic peoples’ local foods.

When Fairbanks, Alaska, got 1.4 inches of freezing rain in December 2021, the moisture created an ice layer that persisted for months, bringing down trees and disrupting travel, infrastructure and the ability of some Arctic animals to forage for food. The resulting ice layer was largely responsible for the deaths of a third of a bison herd in interior Alaska.

There are multiple reasons for this increase in Arctic precipitation.

As sea ice rapidly declines, more open water is exposed, which feeds increased moisture into the atmosphere. The entire Arctic region has seen a more than 40% loss in summer sea ice extent over the 44-year satellite record.

The Arctic atmosphere is also warming more than twice as fast as the rest of the globe, and this warmer air can hold more moisture.

Map and time series chart show the continuing decline of the maximum extent of Arctic sea ice. — NOAA Climate.gov

Under the ground, the wetter, rainier Arctic is accelerating the thaw of permafrost, upon which most Arctic communities and infrastructure are built. The result is crumbling buildings, sagging and cracked roads, the emergence of sinkholes and the collapse of community coastlines along rivers and ocean.

Wetter weather also disrupts the building of a reliable winter snowpack and safe, reliable river ice, and often challenges Indigenous communities’ efforts to harvest and secure their food.

When Typhoon Merbok hit in September 2022, fueled by unusually warm Pacific water, its hurricane-force winds, 50-foot waves and far-reaching storm surge damaged homes and infrastructure over 1,000 miles of Bering Sea coastline, and disrupted hunting and harvesting at a crucial time.

Globe and time series chart show temperatures rising faster across the Arctic than in the rest of the world. — NOAA Climate.gov

Arctic snow season is shrinking

Snow plays critical roles in the Arctic, and the snow season is shrinking.

Snow helps to keep the Arctic cool by reflecting incoming solar radiation back to space, rather than allowing it to be absorbed by the darker snow-free ground. Its presence helps lake ice last longer into spring and helps the land to retain moisture longer into summer, preventing overly dry conditions that are ripe for devastating wildfires.

Snow is also a travel platform for hunters and a habitat for many animals that rely on it for nesting and protection from predators.

A shrinking snow season is disrupting these critical functions. For example, the June snow cover extent across the Arctic is declining at a rate of nearly 20% per decade, marking a dramatic shift in how the snow season is defined and experienced across the North.

Even in the depth of winter, warmer temperatures are breaking through. The far northern Alaska town of Utqiaġvik hit 40 degrees Fahrenheit (4.4 C) – 8 F above freezing – on Dec. 5, 2022, even though the sun does not breach the horizon from mid-November through mid-January.

Map and time series chart show how June snowfall has decreased since the late 1970s. — NOAA Climate.gov

Fatal falls through thin sea, lake and river ice are on the rise across Alaska, resulting in immediate tragedies as well as adding to the cumulative human cost of climate change that Arctic Indigenous peoples are now experiencing on a generational scale.

Greenland ice melt means global problems

The impacts of Arctic warming are not limited to the Arctic. In 2022, the Greenland ice sheet lost ice for the 25th consecutive year. This adds to rising seas, which escalates the danger coastal communities around the world must plan for to mitigate flooding and storm surge.

In early September 2022, the Greenland ice sheet experienced an unprecedented late-season melt event across 36% of the ice sheet surface. This was followed by another, even later melt event that same month, caused by the remnants of Hurricane Fiona moving up along eastern North America.

International teams of scientists are dedicated to assessing the scale to which the Greenland ice sheet’s ice formation and ice loss are out of balance. They are also increasingly learning about the transformative role that warming ocean waters play.

This year’s Arctic Report Card includes findings from the NASA Oceans Melting Greenland (OMG) mission that has confirmed that warming ocean temperatures are increasing ice loss at the edges of the ice sheet.

Human-caused change is reshaping the Arctic

We are living in a new geological age — the Anthropocene — in which human activity is the dominant influence on our climate and environments.

In the warming Arctic, this requires decision-makers to better anticipate the interplay between a changing climate and human activity. For example, satellite-based ship data since 2009 clearly show that maritime ship traffic has increased within all Arctic high seas and national exclusive economic zones as the region has warmed.

Map shows increase in ship traffic in Arctic regions since 2009, with a nearly 50% increase in shipping around Norway and over 12% increase near Russia. Paired with a photo of a ship in sea ice. — NOAA Climate.gov

For these ecologically sensitive waters, this added ship traffic raises urgent concerns ranging from the future of Arctic trade routes to the introduction of even more human-caused stresses on Arctic peoples, ecosystems and the climate. These concerns are especially pronounced given uncertainties regarding the current geopolitical tensions between Russia and the other Arctic states over its war in Ukraine.

Rapid Arctic warming requires new forms of partnership and information sharing, including between scientists and Indigenous knowledge-holders. Cooperation and building resilience can help to reduce some risks, but global action to rein in greenhouse gas pollution is essential for the entire planet.

Matthew L. Druckenmiller, Research Scientist, National Snow and Ice Data Center (NSIDC), Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado Boulder; Rick Thoman, Alaska Climate Specialist, University of Alaska Fairbanks, and Twila Moon, Deputy Lead Scientist, National Snow and Ice Data Center (NSIDC), Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado Boulder

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

13 11 2022

Manager agriculture, biodiversity, carbon budget, flood, forestry, impacts, land use, maladaptation, nature based solutions biodiversity, forestry, land use

This is such a compelling press release that it’s worth reprinting in full, here:

“The Environmental Defence Society and Pure Advantage have joined forces to draft a submission on the review of the National Environmental Standards for Plantation Forestry (the Standards). The submission seeks significant tightening of the rules governing exotic forest management in Aotearoa New Zealand.

“Our submission starts with the premise that forest practices here are out of step with the rest of the developed world. There are inadequate controls over sediment, slash and soil stability and the sector needs to lift its environmental performance across all of its activities,” said EDS COO Shay Schlaepfer.

“With that in the mind, the scope of the current review, which is focused on permanent exotic carbon forests, is too narrow and we are calling on Government to undertake a fundamental reset of the regulations.“Our submission points to the following key problems with the present Standards:

It fails to effectively address adverse environmental outcomes associated with plantation forestry activities

It is unjustifiably and unlawfully permissive for such high risk activities, particularly with regard to afforestation on highly erodible land and clear fell harvesting

It fails to adequately recognise and encourage the wider and longer-term intergenerational climate resilience, biodiversity, social, cultural, and economic opportunities associated with indigenous forests

It is insufficiently aligned with national objectives and direction in relation to freshwater, coastal, and indigenous biodiversity protection and long-term carbon sequestration.

“Put in simple terms, the current Standards are failing to address significant adverse environmental effects associated with where trees are planted, whattrees are planted, and how forests are managed and harvested. These effects need to be managed for both new so-called permanent carbon forests and plantation forests.

“We contend that the presumption in the current Standards that forestry activities are “permitted” is unworkable, inappropriate, and ineffective at securing environmental protection.

“We are releasing our draft submission to give some guidance to others wishing to see improvements in the way exotic forests are managed. The intention is to file the final submission on the closing date which is 18 November,” said Ms Schlaepfer.

“The draft submission is available here and feedback can be sent to [email protected]

29 09 2022

Manager carbon budget, emissions trading scheme, forestry, maladaptation, nature based solutions, pine, risk biodiversity, emissions trading scheme, flood, forestry, pine

Top image: PureAdvantage

Reposted from Pure Advantage:

There is a new risk to you – the taxpayer – from the government’s recent decision to back off from excluding exotic species like pine from the permanent forest category of the emissions trading scheme.

From 1 January 2023 forest owners can lock up pine plantations, as ‘permanent forests’. In return, while the trees are growing, owners will be able to earn credits which they can sell to polluting industries to offset emissions. When the trees stop growing those revenue streams finish. This means pine plantations will increasingly be planted with no intent to harvest. A new exotic carbon farming industry will rapidly spread across the land–an industry we can think of as carbon mining.

Just like its traditional format, carbon mining is an extractive industry. Once there is no resource left–in this case, when the pine trees stop growing–the mine is of no value and becomes a liability.

In addition to the long-term costs of managing a plantation in its ‘permanent’ state, any deforestation requires the owners to buy emission units. There is a very real risk of a ticking time bomb with the price of emissions units increasing significantly over time.

Pinus radiata is an introduced species, unlike native forests with diversity and climate resilience. With increasing impacts from climate change, pine plantations present heightened risks.

They burn well, creating risks for neighbours and releasing CO2 back into the atmosphere. The recent wildfires in the Landes forest, the largest planted forest in western Europe, saw thousands of hectares burnt and thousands of people evacuated.

These are monocultures, at a time when a biodiversity crisis and collapsing ecosystems are posing risks to human survival. In NZ, they are also monoclones, with a lack of genetic diversity that makes them very vulnerable to climate change. In many parts of the world, pests and diseases are wiping out huge areas of pine plantations.

Pinus radiata is also a relatively short-lived species, especially in New Zealand due to intensive genetic modification. Compared with native forests, pine plantations sequester carbon for a relatively brief period. As the trees age and die, the risks of fire and disease increase, along with the risks that the plantations will be abandoned.

Promises may be made that instead, pine plantations will be converted to native forests. This is a very difficult and high risk process, however. Take for example Maungataniwha pine plantation.

It can take at least a decade to clear logged land of wilding pines and to get it to the point where it can be described as fully regenerated – supposing you are lucky enough to have native seeds in the soil already. It’s costing the Forest Lifeforce Restoration Trust around $70,000 per year, plus a lot of volunteer hours.

If land owners are not inclined or able to meet their obligations, these sorts of projects will be extremely challenging. Government and communities will pick up the costs of remediation.

Millions more would be needed to pay for the purchase of emission units to offset the felled pine, and it is hard to see where this money would come from.

As designed, the ETS is encouraging the misallocation of capital towards carbon mining, with the potential for damaging long-term socio-economic and biodiversity outcomes.

Ultimately, taxpayers and society will be left with the bill. The environment will suffer, biodiversity will be negatively impacted, resilience to climate change will be reduced and you, me, our children will be picking up the bill.