One of Earth’s most biodiverse habitats lies off the Scottish west coast – but climate change could wipe it out


Lukassek/Shutterstock

Heidi Burdett, Heriot-Watt University and Cornelia Simon-Nutbrown, Heriot-Watt University

Maerl beds stud the ocean floor like underwater brambles. They’re pastel pink and, despite their knobbly appearance, made up of a red seaweed. This algae has a limestone skeleton which gives it a complex three-dimensional structure that is quite unlike the slimy seaweeds you may be more familiar with.

In fact, the closest thing to a maerl bed you’ve probably heard of is a coral reef. Like tropical reefs, the seaweeds in maerl beds interlock as they grow, creating nooks and crannies that serve as the perfect home for a huge range of sealife. Maerl beds are one of the world’s most biodiverse habitats, but unlike coral reefs, few people have heard of them and even fewer study them.

Also known as “rhodolith beds”, maerl beds are found in coastal waters all over the world, from the poles to the equator, but pockets of this habitat form European strongholds off Scotland’s west coast and islands. Sadly, our new research has revealed how climate change threatens to destroy much of this natural heritage before its wonders have been brought to light.

A clump of knobbly, pink, coralline seaweed.
A piece of Scottish maerl that is well over 100 years old.
Nick Kamenos, Author provided

Climate change and maerl beds

Maerl grows at a glacial pace – just 0.2 mm per year in Scotland. This makes it difficult for these habitats to respond to rapid changes in water temperature or ocean currents. But these are just the kind of environmental changes that are expected around Scotland over the coming century.

Until recently, scientists had only conducted small-scale experiments on maerl, so we knew very little about how Scotland’s beds would respond to climate change. To overcome this, we developed a computer model that can predict how the multiple changes to Scotland’s climate will affect the distribution of this habitat by 2100.

Astonishingly, even in the best-case scenario, where emissions are rapidly reduced from current levels, we predict that maerl bed distribution will shrink by 38% by the end of the century. If global emissions stick to their current trajectory, we predict a massive 84% decline in maerl bed distribution around Scotland. Without major changes we will likely follow this path, or worse.

Our research tells us that this would be devastating for the flora and fauna that call this habitat home, including commercially important species such as juvenile pollack, hake and scallops.

Scotland’s maerl beds under ‘worst-case’ warming scenario

Two maps comparing maerl bed distribution off the Scottish coast today and in 2100.

Simon-Nutbrown et al. (2020), Author provided

Refuge areas

Only international efforts to rapidly reduce greenhouse gas emissions could improve the situation for Scotland’s maerl beds. But managing the coastal ocean better – with regulation of trawling and pollution – could soften the blow. Since our model found that the rate of habitat decline will be fastest between now and 2050, the need for rapid action is even more urgent.

It’s unrealistic to expect the entire coastal ocean of a country to be placed under strict marine protection. After all, these regions are very valuable to a range of industries and interests, like tourism, shipping and fishing. Where then, should we focus our efforts? Our computer model helps with this too.

We have identified some key areas in which maerl populations are likely to persist in local micro-climates. Here, temperatures are not predicted to rise as much as the surrounding water and changes in waves and currents at the seafloor are expected to be less pronounced. This will allow maerl beds to remain in areas such as Loch Laxford, mainland Orkney and mainland Shetland. Protecting and monitoring these refuge areas could maximise the chances of these habitats surviving for future generations to enjoy.

Seafloor habitat with pink clumps of maerl, rocks and seaweed.
A Scottish maerl bed brimming with life.
Nick Kamenos, Author provided

Knowing where a habitat might continue to thrive in the future is crucial for planning how to manage coastal seas better, and being able to map these areas can help reconcile their protection with other activities. The refuge areas we found will now be considered as priority conservation areas by the Scottish Government.

Climate change is expected to affect maerl beds all around the world, so the computer model we’ve created can now find other areas where they may be able to cling on globally. Conservation can be long, gruelling work, so being able to focus marine protection efforts in areas with the highest chance of survival could help safeguard at least some of this habitat for future generations.The Conversation

Heidi Burdett, Research Fellow, Lyell Centre for Earth and Marine Science and Technology, Heriot-Watt University and Cornelia Simon-Nutbrown, PhD Candidate in Marine Conservation, Heriot-Watt University

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

The ocean is swimming in plastic and it’s getting worse – we need connected global policies now



Fotos593 / shutterstock

Steve Fletcher, University of Portsmouth and Keiron Philip Roberts, University of Portsmouth

It seems you cannot go a day without reading about the impact of plastic in our oceans, and for good reason. The equivalent of a garbage truck of plastic waste enters the sea every minute, and this increases every day. If we do nothing, by 2040 the amount of plastic entering the ocean will triple from 13 million tonnes this year, to 29 million tonnes in 2040. That is 50kg of waste plastic entering the ocean for every metre of coastline.

Add to that almost all the plastic that has entered the ocean is still there since it takes centuries to break down. It is either buried or broken down into smaller pieces and potentially passes up the food chain creating further problems.

Despite this, plastic has also been a saviour. During the COVID-19 pandemic plastic used in face masks, testing kits, screens and to protecting food has enabled countries to come out of lockdown during and support social distancing. We still need to use these items until sustainable and “COVID safe” alternatives are available. But we also need to look to the future to reduce our dependence on plastic and its impact on the environment. With plastic in the ocean being a global problem, we need global agreements and policies to reverse the plastic tide.




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Ambitious policies are needed

Environment ministers of the G20 group of the world’s most economically powerful countries and regions met on September 16 to discuss their immediate challenges, with marine plastic pollution a top priority. A key item for discussion was “safeguarding the planet by fostering collective efforts to protect our global commons”. This means working out how we can continue to use the planet’s resources sustainably without harming the environment.

A global analysis of plastics policies over the past two decades found that typical reactions to marine plastic litter were bans or taxes on individual or groups of plastic items within single countries. So far, 43 countries have introduced a ban, tax or levy on plastic bags. Other plastic packaging or single-use plastic products were banned in at least 25 countries, representing a population of almost 2 billion people in 2018.

But plastic waste doesn’t respect land or ocean borders, with mismanaged plastic waste easily migrating from country to country when leaked into the environment. Policies also need to consider the entire plastics life cycle to stand a chance of being effective. For example, the inclusion of easier to recycle plastics in consumer products sounds positive, but their actual recycling rate depends on effective sorting and collection of plastic waste, and appropriate infrastructure being in place.




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Ultimately, a joined up but adaptable set of rules and guidelines are needed so all plastic producers and users can prevent its leakage across all stages of the plastics life cycle.

The G20 has sought to lead action on marine plastic litter through a 2017 Action Plan on Marine Litter which set out areas of concern and possible policy interventions, and through connections to initiatives such as the UN Environment Programme’s Global Partnership on Marine Litter and most recently the Osaka Blue Ocean Vision. The Osaka vision was agreed under the Japanese G20 presidency in 2019 and commits countries to “reduce additional pollution by marine plastic litter to zero by 2050”. Although an agreement led by the G20, it now has the support of 86 countries.

But even with these agreements in place, plastic entering the ocean will still only reduce by 7% by 2040. We need ambitious new agreements as current and emerging policies do not meet the scale of the challenge.

A consensus is forming that the G20 and other global leaders must focus on a systemic change of the plastics economy. This includes focusing on “designing out” plastics, promoting technical and business innovation, immediately scaling up actions known to reduce marine plastic litter, and transitioning to a circular economy in which materials are fully recovered and reused. These actions have the potential to contribute to the G20’s vision of net-zero plastics entering the ocean by 2050, but only if ambitious actions are taken now.The Conversation

Steve Fletcher, Professor of Ocean Policy and Economy, University of Portsmouth and Keiron Philip Roberts, Research Fellow in Clean Carbon Technologies and Resource Management, University of Portsmouth

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

Ocean warming threatens coral reefs and soon could make it harder to restore them



Climate-driven ocean warming threatens healthy coral reefs, like this one in Hawaii.
Shawna Foo, CC BY-ND

Shawna Foo, Arizona State University

Graphic stating that at 86.9 degrees Fahrenheit, the chance of transplanted corals surviving falls below 50%

CC BY-ND

Anyone who’s tending a garden right now knows what extreme heat can do to plants. Heat is also a concern for an important form of underwater gardening: growing corals and “outplanting,” or transplanting them to restore damaged reefs.

The goal of outplanting is to aid coral reefs’ natural recovery process by growing new corals and moving them to the damaged areas. It’s the same idea as replanting forests that have been heavily logged, or depleted farm fields that once were prairie grasslands.

I have studied how global stressors such as ocean warming and acidification affect marine invertebrates for more than a decade. In a recently published study, I worked with Gregory Asner to analyze the impacts of temperature on coral reef restoration projects. Our results showed that climate change has raised sea surface temperatures close to a point that will make it very hard for outplanted corals to survive.

Coral gardening

Coral reefs support over 25% of marine life by providing food, shelter and a place for fish and other organisms to reproduce and raise young. Today, ocean warming driven by climate change is stressing reefs worldwide.

Rising ocean temperatures cause bleaching events – episodes in which corals expel the algae that live inside them and provide the corals with most of their food, as well as their vibrant colors. When corals lose their algae, they become less resistant to stressors such as disease and eventually may die.

Hundreds of organizations worldwide are working to restore damaged coral reefs by growing thousands of small coral fragments in nurseries, which may be onshore in laboratories or in the ocean near degraded reefs. Then scuba divers physically plant them at restoration sites.

Outplanting is the process of transplanting nursery-grown corals onto reefs.

Outplanting coral is expensive: According to one recent study, the median cost is about US$160,000 per acre, or $400,000 per hectare. It also is time-consuming, with scuba divers placing each outplanted coral by hand. So it’s important to maximize coral survival by choosing the best locations.

We used data from the National Oceanic and Atmosphere Administration’s Coral Reef Watch program, which collects daily satellite-derived measurements of sea surface temperature. We paired this information with survival rates from hundreds of coral outplanting projects worldwide.

We found that coral survival was likely to drop below 50% if the maximum temperature experienced at the restoration site exceeded 86.9 degrees Fahrenheit (30.5 degrees Celsius). This temperature threshold mirrors the tolerance of natural coral reefs.

Globally, coral reefs experience an annual maximum temperature today of 84.9˚F (29.4˚C). This means they already are living close to their upper thermal limit.

When reefs experience temperatures only a few degrees above long-term averages for a few weeks, the stress can cause coral bleaching and mortality. Increases of just a few degrees above normal caused three mass bleaching events since 2016 that have devastated Australia’s Great Barrier Reef.

Map of global sea surface temperatures, color coded to show bleaching risks.
Sea surface temperatures on Aug. 3, 2020, measured from satellites. Warning = possible bleaching; Alert Level 1 = significant bleaching likely; Alert Level 2 = severe bleaching and significant mortality likely.
NOAA Coral Reef Watch

Warmer oceans

Climate scientists project that the oceans will warm up to 3˚C by the year 2100. Scientists are working to create coral outplants that can better survive increases in temperature, which could help to increase restoration success in the future.

When coral restoration experts choose where to outplant, they typically consider what’s on the seafloor, algae that could smother coral, predators that eat coral and the presence of fish. Our study shows that using temperature data and other information collected remotely from airplanes and satellites could help to optimize this process. Remote sensing, which scientists have used to study coral reefs for almost 40 years, can provide information on much larger scales than water surveys.

Coral reefs face an uncertain future and may not recover naturally from human-caused climate change. Conserving them will require reducing greenhouse gas emissions, protecting key habitats and actively restoring reefs. I hope that our research on temperature will help increase coral outplant survival and restoration success.

[Get our best science, health and technology stories. Sign up for The Conversation’s science newsletter.]The Conversation

Shawna Foo, Postdoctoral Research Scholar, Arizona State University

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

Why we’re working to put Africa’s jellyfish on the map



New Chrysaora from the coast of South Africa.
Peter Southwood

Verena Ras, University of the Western Cape

Jellyfish can be found in almost every ocean in the world. These beautiful, graceful creatures are a sight to behold; their swift, pulsating motions gently propel them through the water. But the scene can quickly turn ominous as the animal transforms into a ferocious, formidable predator.

These creatures have no special organs for respiration or excretion. They have no head, no brain, no skeleton and no true circulatory system. This allows them to be highly adaptable and to survive in even the harshest conditions.

Most species typically have a multi-phase life cycle. Many jellyfish can exist as polyps on the sea floor, able to create identical clones of themselves. When conditions are just right, polyps are able to release numerous juvenile jellies into the water. Many polyps may even lie dormant when conditions are not favourable, emerging again when they improve. The free-swimming adult jellyfish often eat a variety of marine species from tiny shrimp to small pelagic fish. Many even eat other jellies. The adult jelly can also shrink when food is not available to conserve energy and resources, growing back to its normal size when food becomes available again. This unique life history gives them many advantages over other species.

Jellyfish are also well known for forming large swarms known as “blooms” – which can have far reaching negative effects. Jellyfish blooms have clogged the cooling intakes of power plants, resulting in total shutdowns; they can destroy fishing nets and spoil catches. Many species also deliver a painful sting that many beach-goers may know well.

But despite some of these negative impacts, jellyfish are incredibly useful. They are indicators of oceanic circulation patterns, play a rather large role in the mixing of oceanic nutrients and also help control pelagic fish populations (those that inhabit the water column, not near the bottom or the shore). It was recently discovered that jellyfish even provide microhabitats where other marine species may live and survive.

Jellyfish have also recently become the focus of a number of biotechnology and pharmaceutical studies as they appear to possess many properties that may be useful in a variety of applications, from household cleaning products to fertilisers. Other species are now commercially farmed for human consumption, with large fisheries already established in countries like India and China. Jellyfish are being turned into products like dehydrated chips, protein shakes and other food stuffs.

However, with few dedicated research efforts, jellyfish remain unexplored in many oceans and it is likely that many species have gone unrecorded or unnoticed. Some scientists even suggest that their numbers may be declining in some parts of the world. Global longterm data simply doesn’t exist for jellyfish, so scientists struggle to predict, track and mitigate their potential effects – good and bad.

But collecting the necessary data requires significant resources, manpower and expertise. That’s where a South African-led team of researchers based at the University of the Western Cape’s Department of Biodiversity and Conservation Biology comes in. Using samples collected by a global research vessel, we’ve been able to begin to establish a baseline of data for African jellyfish species. This, we hope, will allow us to establish more thorough trends across oceans, uncover new species (we’ve already identified one) and better understand the links between different species.

Examining the specimens

In 2016, we approached the Food and Agriculture Organisation’s EAF-NANSEN Programme to see whether jellyfish samples could be collected by its Dr Fridtjof Nansen research vessel. EAF-NANSEN agreed, and started collecting samples in waters across the African continent.

The first specimens arrived at UWC late in 2017 and we got to work. Jellyfish have few identifying features and a highly variable body type. So figuring out which species we had in the lab was no easy task. The team typically measures anywhere from 35 to 70 morphological features for any given species, which are then analysed statistically for patterns. DNA is also extracted from various individuals and populations to help identify species and to establish patterns of gene flow across populations.

So, what have we learned? First, it became clear early on that the African coastline encompasses a larger variety of species than previously thought. Our group has already found a new compass jelly off the southern coast of South Africa, along with a new species of rhizostome jellyfish that appears to be completely endemic to South Africa through some of our previous research.

University of the Western Cape masters student Roxy Zunckel swims with the jellyfish Rhizostoma luteum.
Supplied

Second, the team has begun to identify a number of other African morphotypes that appear to be distinct from their global counterparts. The species found here appear to show high levels of endemism, meaning they are changing in their physical appearance and even their DNA to adapt to our waters.

The work is continuing and we have already received three years’ worth of specimens and associated data which we hope to analyse alongside other African jelly experts.

Future plans

The aim of this work is to build up and establish high quality resources for African jellyfish species that may be used to contribute to global studies and reviews. Eventually, we hope to establish population patterns across the east and west African coastlines; at the moment these data simply don’t exist. This will require a coordinated global effort, but as we’ve shown through our collaboration with the NANSEN programme, this is possible and it’s yielding great results.The Conversation

Verena Ras, PhD candidate, University of the Western Cape

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

Pacific Islands must stop relying on foreign aid to adapt to climate change, because the money won’t last



Patrick Nunn, Author provided

Patrick D. Nunn, University of the Sunshine Coast and Roselyn Kumar, University of the Sunshine Coast

The storm of climate change is approaching the Pacific Islands. Its likely impact has been hugely amplified by decades of global inertia and the islands’ growing dependency on developed countries.

The background to this situation is straightforward. For a long time, richer developed countries have been underwriting the costs of climate change in poorer developing countries, leaving them reliant on Western solutions to their climate-related issues.




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But as rising sea water continues to encroach on these low-lying Pacific islands, inundating infrastructure and even cemeteries, it’s clear almost every externally sponsored attempt at climate adaptation has failed here.

And as the costs of adaptation in richer countries escalate, this funding support to developing countries will likely taper out in future.

We’ve researched climate change adaptation in the Pacific for more than 50 years. We argue this trend is not merely unsustainable, but also dangerous. Pacific Island nations must start drawing from traditional knowledge to adapt to climate change, rather than continue to rely on foreign funds.

The ruins of a sea wall on a coastline.
High waves destroyed this sea wall on Majuro Atoll (Marshall Islands).
Patrick Nunn, Author provided

Western solutions don’t always work

On a global scale, climate adaptation strategies have largely been either ineffective or unsustainable.

This is especially the case in non-Western contexts, where Western science continues to be privileged. In the Pacific Islands, this is often because these Western strategies invariably subordinate, even ignore, funding recipients’ culturally grounded worldviews.

A good example is the desire of foreign donors to build hard structures, such as sea walls, to protect eroding coasts. This is the preferred strategy in richer nations.

However it does not embrace nature-based solutions such as replanting coastal mangroves, which can be more readily sustained in poorer contexts.

A likely scenario

The availability of external financial assistance means developing countries have become more dependent on their richer counterparts for climate change adaptation.

For example, between 2016 and 2019, Australia provided A$300 million to help Pacific Island nations adapt to climate change, committing to a further $500 million to 2025. This left little need or incentive for these countries to fund their own adaptation needs.




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But imagine this climate change scenario. Ten years from now, unprecedented rainfall is dumped on Australia’s east coast over a prolonged period. Several cities become flooded and remain so for weeks.

In the aftermath, the Australian government scrambles to make recently flooded areas liveable once more. They build a series of massive coastal dikes – structures to prevent the rising sea from flooding populated areas.

The cost is exorbitant and unanticipated – like COVID-19 – so the government will look for ways to shuffle money around. This may well include reducing financial aid for climate change adaptation in poorer countries.

Plunging international aid

Economic modelling shows nations will incur massive costs this century to adapt to climate change within their own borders. So it’s almost inevitable wealthier countries will rethink the extent of their assistance to the developing world.

A chart showing the projected adaptation aid to the Pacific Islands.
Recent and projected Australian GDP and adaptation aid to Pacific Island.
countries.

Patrick Nunn, Author provided

In fact, even before the pandemic, Australia’s foreign aid budget was projected to decrease in real terms by nearly 12% from 2020 to 2023.

These factors do not bode well for developing countries, which will be facing higher climate adaptation costs and dwindling foreign aid assistance.




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Building autonomy with ‘cashless adaptation’

Leaders of developing countries should anticipate this situation now, and reverse their growing dependence on outside assistance.

For example, rural communities in regions like the Pacific Islands could revive their use of “cashless adaptation”. This means developing ways of adapting livelihoods to climate change that cost nothing.

These methods include the intentional planting of surplus crops, the use of traditional methods of food preservation and water storage, the use of free locally-available materials and labour for constructing sea defences. And it perhaps even includes the recognition that living along coastal fringes exposes you unnecessarily to weather-related change.

Prior to globalisation, this is how it was for decades, even centuries, in places like the rural Pacific islands. Then, adaptation to a changing environment was sustained by cooperation with one another and the use of freely available materials, not with cash.

Researchers have also argued for such “looking forward to the past” strategies regarding Hawaii’s climate adaptation.

And research from last year in Fiji showed more rural communities still have and use a stock of traditional methods for anticipating and withstanding disasters, such as flood and drought.




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We can take this argument further. Perhaps it’s time for Pacific Island nations to rediscover traditional medicines, at least for primary health care, to supplement western medicine.

Greater production and consumption of locally grown foods, over imported foods, is also an important and valuable transformation.

The future of the developing world

A hut with a large pointed roof, built with local materials.
Dirak faluw (‘men’s house’) at Wanyaan Village on Yap (Micronesia) was.
constructed by community labour using local-available materials.

Roselyn Kumar, Author provided

The need for nations to adapt to unanticipated phenomena like climate change and COVID-19 encourages de-globalisation – including that countries depend less on cross-border aid and economic activity. So it seems inevitable that under current global circumstances, smaller economies will be forced to become more efficient and self-reliant.

Restoring traditional adaptation strategies would not only drive effective and sustainable climate change adaptation, but also would restore residents’ beliefs in their own time-honoured ways of coping with environmental shocks.

This not only means finding ways to reduce costs through cashless adaptation, but also to explore radical ways of reducing dependency and increasing autonomy. An appeal to past practice, and traditional ways of coping, is well worth considering.The Conversation

Patrick D. Nunn, Professor of Geography, School of Social Sciences, University of the Sunshine Coast and Roselyn Kumar, , University of the Sunshine Coast

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

Storm warning: a new long-range tropical cyclone outlook is set to reduce disaster risk for Pacific Island communities



Photobank.kiev.ua/Shutterstock

Andrew Magee, University of Newcastle; Andrew Lorrey, National Institute of Water and Atmospheric Research, and Anthony Kiem, University of Newcastle

Tropical cyclones are among the most destructive weather systems on Earth, and the Southwest Pacific region is very exposed and vulnerable to these extreme events.

Our latest research, published today in Scientific Reports, presents a new way of predicting the number of tropical cyclones up to four months ahead of the cyclone season, with outlooks tailored for individual island nations and territories.

A new model predicts tropical cyclone counts up to four months in advance.

Tropical cyclones produce extreme winds, large waves and storm surges, intense rainfall and flooding — and account for almost three in four natural disasters across the Southwest Pacific region.

Currently, Southwest Pacific forecasting agencies release a regional tropical cyclone outlook in October, one month ahead of the official start of the cyclone season in November. Our new model offers a long-range warning, issued monthly from July, to give local authorities more time to prepare.

Most importantly, this improvement on existing extreme weather warning systems may save more lives and mitigate damage by providing information up to four months ahead of the cyclone season.

This map shows the expected number of tropical cyclones for the 2020/21 Southwest Pacific cyclone season (November to April).
http://www.tcoutlook.com/latest-outlook, Author provided

Tropical cyclones and climate variability

An average of 11 tropical cyclones form in the Southwest Pacific region each season. Since 1950, tropical cyclones have claimed the lives of nearly 1500 and have affected more than 3 million people.

In 2016, Cyclone Winston, a record-breaking severe category 5 event, was the strongest cyclone to make landfall across Fiji. It killed 44 people, injured 130 and seriously damaged around 40,000 homes. Damages totalled US$1.4 billion — making it the costliest cyclone in Southwest Pacific history.




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Tropical cyclones are erratic in their severity and the path they travel. Every cyclone season is different. Exactly where and when a tropical cyclone forms is driven by complex interactions between the ocean and the atmosphere, including the El Niño-Southern Oscillation, sea surface temperatures in the Indian Ocean, and many other climate influences.

Capturing changes in all of these climate influences simultaneously is key to producing more accurate tropical cyclone outlooks. Our new tool, the Long-Range Tropical Cyclone Outlook for the Southwest Pacific (TCO-SP), will assist forecasters and help local authorities to prepare for the coming season’s cyclone activity.

This map shows the probability of below or above-average tropical cyclones for the 2020/21 Southwest Pacific cyclone season.
http://www.tcoutlook.com/latest-outlook, Author provided

According to the latest long-range sea surface temperature outlook, there is a 79% chance that La Niña conditions could develop before the start of the 2020-21 Southwest Pacific cyclone season. La Niña conditions typically mean the risk of tropical cyclone activity is elevated for island nations in the western part of the region (New Caledonia, Solomon Islands and Vanuatu) and reduced for nations in the east (French Polynesia and the Cook Islands). But there are exceptions, particularly when certain climate influences like the Indian Ocean Dipole occur with La Niña events.




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Improving existing tropical cyclone guidance

Current guidance on tropical cyclones in the Southwest Pacific region is produced by the National Institute of Water and Atmospheric Research, the Australian Bureau of Meteorology and the Fiji Meteorological Service. Each of these organisations uses a different method and considers different indices to capture ocean-atmosphere variability associated with the El Niño-Southern Oscillation.

Our research adds to the existing methods used by those agencies, but also considers other climate drivers known to influence tropical cyclone activity. In total, 12 separate outlooks are produced for individual nations and territories including Fiji, Solomon Islands, New Caledonia, Vanuatu, Papua New Guinea and Tonga.

Other locations are grouped into sub-regional models, and we also provide outlooks for New Zealand because of the important impacts there from ex-tropical cyclones.

Our long-range outlook is a statistical model, trained on historical relationships between ocean-atmosphere processes and the number of tropical cyclones per season. For each target location, hundreds of unique model combinations are tested. The one that performs best in capturing historical tropical cyclone counts is selected to make the prediction for the coming season.

At the start of each monthly outlook, the model retrains itself, taking the most recent changes in ocean temperature and atmospheric variability and attributes of tropical cyclones from the previous season into account.

Both deterministic (tropical cyclone numbers) and probabilistic (the chance of below, normal or above average tropical cyclone activity) outlooks are updated every month between July and January and are freely available.The Conversation

Andrew Magee, Postdoctoral Researcher, University of Newcastle; Andrew Lorrey, Principal Scientist & Programme Leader of Climate Observations and Processes, National Institute of Water and Atmospheric Research, and Anthony Kiem, Associate Professor – Hydroclimatology, University of Newcastle

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

With no work in lockdown, tour operators helped find coral bleaching on Western Australia’s remote reefs



Jeremy Tucker, Author provided

James Paton Gilmour, Australian Institute of Marine Science

Significant coral bleaching at one of Western Australia’s healthiest coral reefs was found during a survey carried out in April and May.

The survey took a combined effort of several organisations, together with tour operators more used to taking tourists, but with time spare during the coronavirus lockdown.

WA’s arid and remote setting means many reefs there have escaped some of the pressures affecting parts of the east coast’s Great Barrier Reef), such as degraded water quality and outbreaks of crown of thorns starfish.

The lack of these local pressures reflects, in part, a sound investment by governments and communities into reef management. But climate change is now overwhelming these efforts on even our most remote coral reefs.

Significant coral bleaching has been identified at WA reefs.
Nick Thake, Author provided

When the oceans warmed

This year, we’ve seen reefs impacted by the relentless spread of heat stress across the world’s oceans.

As the 2020 mass bleaching unfolded across the Great Barrier Reef, a vast area of the WA coastline was bathed in hot water through summer and autumn. Heat stress at many WA reefs hovered around bleaching thresholds for weeks, but those in the far northwest were worst affected.

The remoteness of the region and shutdowns due to COVID-19 made it difficult to confirm which reefs had bleached, and how badly. But through these extraordinary times, a regional network of collaborators managed to access even our most remote coral reefs to provide some answers.




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Australia’s Bureau of Meteorology provided regional estimates of heat stress, from which coral bleaching was predicted and surveys targeted.

At reefs along the Kimberley coastline, bleaching was confirmed by WA’s Department of Biodiversity, Conservation and Attractions (DBCA), Bardi Jawi Indigenous rangers, the Kimberley Marine Research Centre and tourist operators.

At remote oceanic reefs hundreds of kilometres from the coastline, bleaching was confirmed in aerial footage provided by Australian Border Force.

Subsequent surveys were conducted by local tourist operators, with no tourists through COVID-19 shutdown and eager to check the condition of reefs they’ve been visiting for many years.

The first confirmation of bleaching on remote coral atolls at Ashmore Reef and the Rowley Shoals was provided in aerial images captured by Australian Border Force.
Australian Border Force, Author provided

The Rowley Shoals

Within just a few days, a tourist vessel chartered by the North West Shoals to Shore Research Program, with local operators and a DBCA officer, departed from Broome for the Rowley Shoals. These three reef atolls span 100km near the edge of the continental shelf, about 260km west-north-west offshore.

One of only two reef systems in WA with high and stable coral cover in the last decade, the Rowley Shoals is a reminder of beauty and value of healthy, well managed coral reefs.

But the in-water surveys and resulting footage confirmed the Rowley Shoals has experienced its worst bleaching event on record.

The most recent heatwave has caused widespread bleaching at the Rowley Shoals, which had previously escaped the worst of the regional heat stress.
Jeremy Tucker, Author provided

All parts of the reef and groups of corals were affected; most sites had between 10% and 30% of their corals bleached. Some sites had more than 60% bleaching and others less than 10%.

The heat stress also caused bleaching at Ashmore Reef, Scott Reef and some parts of the inshore Kimberley and Pilbara regions, all of which were badly affected during the 2016/17 global bleaching event.

This most recent event (2019/20) is significant because of the extent and duration of heat stress. It’s also notable because it occurred outside the extreme El Niño–Southern Oscillation phases – warming or cooling of the ocean’s surface that has damaged the northern and southern reefs in the past.

A reef crisis

The impacts from climate change are not restricted to WA or the Great Barrier Reef – a similar scenario is playing out on reefs around the world, including those already degraded by local pressures.

By global standards, WA still has healthy coral reefs. They provide a critical reminder of what reefs offer in terms of natural beauty, jobs and income from fisheries and tourism.

Despite the most recent bleaching, the Rowley Shoals remains a relatively healthy reef system by global standards. But like all reefs, its future is uncertain under climate change.
James Gilmour, Author provided

But we’ve spent two decades following the trajectories of some of WA’s most remote coral reefs. We’ve seen how climate change and coral bleaching can devastate entire reef systems, killing most corals and dramatically altering associated communities of plants and animals.

And we’ve seen the same reefs recover over just one or two decades, only to again be devastated by mass bleaching – this time with little chance of a full recovery in the future climate.

Ongoing climate change will bring more severe cyclones and mass bleaching, the two most significant disturbances to our coral reefs, plus additional pressures such as ocean acidification.

Reducing greenhouse gas emissions is the only way to alleviate these pressures. In the meantime, scientists will work to slow the rate of coral reef degradation though new collaborations, and innovative, rigorous approaches to reef management.The Conversation

James Paton Gilmour, Research Scientist: Coral Ecology, Australian Institute of Marine Science

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

Their fate isn’t sealed: Pacific nations can survive climate change – if locals take the lead


Rachel Clissold, The University of Queensland; Annah Piggott-McKellar, University of Melbourne; Karen E McNamara, The University of Queensland; Patrick D. Nunn, University of the Sunshine Coast; Roselyn Kumar, University of the Sunshine Coast, and Ross Westoby, Griffith University

They contribute only 0.03% of global carbon emissions, but small island developing states, particularly in the Pacific, are at extreme risk to the threats of climate change.

Our study, published today in the journal Nature Climate Change, provides the first mega-assessment on the progress of community-based adaptation in four Pacific Island countries: the Federated States of Micronesia, Fiji, Kiribati and Vanuatu.




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Pacific Island nation communities have always been resilient, surviving on islands in the middle of oceans for more than 3,000 years. We can learn a lot from their adaptation methods, but climate change is an unprecedented challenge.

Effective adaptation is critical for ensuring Pacific Islanders continue living fulfilling lives in their homelands. For Australia’s part, we must ensure we’re supporting their diverse abilities and aspirations.

Short-sighted adaptation responses

Climate change brings wild, fierce and potentially more frequent hazards. In recent months, Cyclone Harold tore a strip through multiple Pacific countries, killing dozens of people, levelling homes and cutting communication lines. It may take Vanuatu a year to recover.

Expert commentary from 2019 highlighted that many adaptation responses in the Pacific have been short-sighted and, at times, even inadequate. The remains of failed seawalls, for example, litter the shorelines of many island countries, yet remain a popular adaptive solution. We cannot afford another few decades of this.




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International climate aid commitments from rich western countries barely scratch the surface of what’s needed, yet it’s likely funding will dry up for regions like the Pacific as governments scramble together money for their own countries’ escalating adaptation costs.

This includes Australia, that has long been, and continues to be, the leading donor to the region. Our government contributed about 40% of total aid between 2011 and 2017 and yet refuses to take meaningful action on climate change.

Understanding what successful adaptation should look like in developing island states is urgent to ensure existing funding creates the best outcomes.

Success stories

Our findings are based on community perspectives. We documented what factors lead to success and failure and what “best practice” might really look like.

We asked locals about the appropriateness, effectiveness, equity, impact and sustainability of the adaptation initiatives, and used this feedback to determine their success.




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The results were mixed. While our success stories illustrate what “best practice” involves, issues still emerged.

Our top two success stories centred on community efforts to protect local marine ecosystems in the Federated States of Micronesia and Vanuatu. Nearby communities rely on these ecosystems for food, income and for supporting cultural practice.

One initiative focused on establishing a marine park with protected areas while the other involved training in crown-of-thorns starfish control. As one person told us:

we think it’s great […] we see the results and know it’s our responsibility.

Initiatives that focus on both the community and the ecosystem support self-sufficiency, so the community can maintain the initiatives even after external bodies leave and funding ceases.

Pele Island, Vanuatu. Can you see coral in the water? The community initiative was aiming to protect this coral ecosystem from crown-of-thorns starfish.
Karen McNamara, Author provided

In these two instances, the “community” was expanded to the whole island and to anyone who utilised local ecosystems, such as fishers and tourism operators.

Through this, benefits were accessible to all: “all men, all women, all pikinini [children],” we were told.

Standing the test of time

In Vanuatu, the locals deemed two initiatives on raising climate change awareness as successful, with new scientific knowledge complementing traditional knowledge.

And in the Federated States of Micronesia, locals rated two initiatives on providing tanks for water security highly. This initiative addressed the communities’ primary concerns around clean water, but also had impact beyond merely climate-related vulnerabilities.

This was a relatively simple solution that also improved financial security and minimised pollution because people no longer needed to travel to other islands to buy bottled water.

Aniwa, Vanuatu. A communal building in the village has a noticeboard, put up as part of one of the climate-awareness raising initiatives.
Rachel Clissold, Author provided

But even among success stories, standing the test of time was a challenge.

For example, while these water security initiatives boosted short-term coping capacities, they weren’t flexible for coping with likely future changes in drought severity and duration.




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Adaptation needs better future planning, especially by those who understand local processes best: the community.

Listening to locals

For an adaptation initiative to be successful, our research found it must include:

  1. local approval and ownership

  2. shared access and benefit for community members

  3. integration of local context and livelihoods

  4. big picture thinking and forward planning.

To achieve these, practitioners and researchers need to rethink community-based adaptation as more than being simply “based” in communities where ideas are imposed on them, but rather as something they wholly lead.

Communities must acknowledge and build on their strengths and traditional values, and drive their own adaptation agendas – even if this means questioning well-intentioned foreign agencies.

Being good neighbours

Pacific Islands are not passive, helpless victims, but they’ll still need help to deal with climate change.

Pacific Island leaders need more than kind words from Australian leaders.




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Last year, Fijian prime minister, Frank Bainimarama, took to Facebook to remind Australia:

by working closely together, we can turn the tides in this battle – the most urgent crisis facing not only the Pacific, but the world.

Together, we can ensure that we are earthly stewards of Fiji, Australia, and the ocean that unites us.

Together, we can pass down a planet that our children are proud to inherit.The Conversation

Rachel Clissold, Researcher, The University of Queensland; Annah Piggott-McKellar, Postdoctoral research fellow, University of Melbourne; Karen E McNamara, Associate professor, The University of Queensland; Patrick D. Nunn, Professor of Geography, School of Social Sciences, University of the Sunshine Coast; Roselyn Kumar, , University of the Sunshine Coast, and Ross Westoby, Research Fellow, Griffith University

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

Climate change threatens Antarctic krill and the sea life that depends on it



Brett Wilks

Devi Veytia, University of Tasmania and Stuart Corney, University of Tasmania

The Southern Ocean circling Antarctica is one of Earth’s richest marine ecosystems. Its food webs support an abundance of life, from tiny micro-organisms to seals, penguins and several species of whales. But climate change is set to disrupt this delicate balance.

Antarctic krill – finger-sized, swarming crustaceans – might be small but they underpin the Southern Ocean’s food web. Our research published today suggests climate change will cause the ocean habitat supporting krill growth to move south. The habitat will also deteriorate in summer and autumn.

The ramifications will reverberate up the food chain, with implications for other Antarctic animals. This includes humpback whales that feed on krill at the end of their annual migration to the Southern Ocean.

Changes in krill habitat could affect species up the food chain including the humpback whale.
Mike Hutchings/AAP

What we found

Antarctic krill are one of the most abundant animal species in the world. About 500 million tonnes of Antarctic krill are estimated to exist in the Southern Ocean.

Antarctic krill play a critical role in the ocean’s food webs. But their survival depends on a delicate balance of food and temperature. Scientists are concerned at how climate change may affect their population and the broader marine ecosystem.

We wanted to project how climate change will affect the Southern Ocean’s krill “growth habitat” – essentially, ocean areas where krill can thrive in high numbers.

Krill growth depends largely on ocean temperature and the abundance of its main food source, phytoplankton (microscopic single-celled plants).




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Under a “business as usual” climate change scenario, future changes in ocean temperature and phytoplankton varied depending on the region and season.

In the mid-low latitudes, our projections showed temperatures warmed towards the limits krill can tolerate. For example, by 2100 the waters during summer around South Georgia island warmed by 1.8℃.

Warming water was often accompanied by decreases in phytoplankton; in the Bellingshausen Sea during summer a 1.7℃ rise halved the available phytoplankton.

However, phytoplankton increased closer to the continent in spring and summer – most dramatically by 175% in the Weddell Sea in spring.

Antarctic krill habitat will shift south under climate change.
Simon Payne, Australian Antarctic Division

Shifting habitat

Across all seasons, krill growth habitat remained relatively stable for 85% of the Southern Ocean. But important regional changes still occurred.

Krill growth habitat shifted south as suitable ocean temperatures contracted towards the poles. Combined with changes in phytoplankton distribution, growth habitat improved in spring but deteriorated in summer and autumn.




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This early end to the growth season could have profound consequences for krill populations. The krill life cycle is synchronised with the Southern Ocean’s dramatic seasonal cycles. Typically this allows krill to both maximise growth and reproduction and store reserves to survive the winter.

A shift in habitat timing could create a mismatch between these two cycles.

For example, female krill need access to plentiful food during the summer in order to spawn. Since larger females produce exponentially more eggs, a decline in summer growth habitat could result in smaller females and far less spawning success.

Antarctic predators including penguins rely on krill for survival.
Royal Navy

Why this matters

Krill’s significant role in the food chain means the impacts of these changes may play out through the entire ecosystem.

If krill shift south to follow their retreating habitat, less food would be available for predators on sub-Antarctic islands such as Antarctic fur seals, penguins and albatrosses for whom krill forms a significant portion of the diet.

In the past, years of low krill densities has coincided with declines in reproductive success for these species.

Shifts in krill habitat timing may also affect migratory predators. For example, each year humpback whales migrate from the tropics to the poles to feed on the huge amount of summer krill. If the krill peak occurs earlier in the season, the whales must adapt by arriving earlier, or be left hungry.

Krill predators. a. crabeater seal (Lobodon carcinophaga), b. Adelie penguins (Pygoscelis adeliae), c. Antarctic fur seal (Arctocephalus gazella), d. humpback whale (Megaptera novaeangliae).
Photo credits (in order a-d): Kevin Neff, Australian Antarctic Division; Mark Hindell, Institute for Marine and Antarctic Studies; Colin Lee Hong, Australian Antarctic Division; Anthony Hull, Australian Antarctic Division.

Looking ahead

Changes to krill growth habitat may damage more than the ocean food web. Demand for krill oil in health supplements and aquaculture feed is on the rise, and krill are the target of the Southern Ocean’s largest fishery. Anticipating changes in krill availability is crucial to informing the fishery’s sustainable management.

Many environmental drivers interact to create good krill habitat. More research is required, including better models, and an improved understanding of what drives krill to reproduce and survive.

But by examining changes in phytoplankton, we’ve taken significant strides towards predicting climate change impacts on krill and the wider Antarctic marine ecosystem.




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The Conversation


Devi Veytia, PhD student , University of Tasmania and Stuart Corney, Senior lecturer, University of Tasmania

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