Extreme weather caused by climate change has damaged 45% of Australia’s coastal habitat



Bleached staghorn coral on the Great Barrier Reef. Many species are dependent on corals for food and shelter.
Damian Thomson, Author provided

Russ Babcock, CSIRO; Anthony Richardson, The University of Queensland; Beth Fulton, CSIRO; Eva Plaganyi, CSIRO, and Rodrigo Bustamante, CSIRO

If you think climate change is only gradually affecting our natural systems, think again.

Our research, published yesterday in Frontiers in Marine Science, looked at the large-scale impacts of a series of extreme climate events on coastal marine habitats around Australia.

We found more than 45% of the coastline was already affected by extreme weather events caused by climate change. What’s more, these ecosystems are struggling to recover as extreme events are expected to get worse.




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There is growing scientific evidence that heatwaves, floods, droughts and cyclones are increasing in frequency and intensity, and that this is caused by climate change.

Life on the coastline

Corals, seagrass, mangroves and kelp are some of the key habitat-forming species of our coastline, as they all support a host of marine invertebrates, fish, sea turtles and marine mammals.

Our team decided to look at the cumulative impacts of recently reported extreme climate events on marine habitats around Australia. We reviewed the period between 2011 and 2017 and found these events have had devastating impacts on key marine habitats.

Healthy kelp (left) in Western Australia is an important part of the food chain but it is vulnerable to even small changes in temperature and particularly slow to recover from disturbances such as the marine heatwave of 2011. Even small patches or gaps (right) where kelp has died can take many years to recover.
Russ Babcock, Author provided

These include kelp and mangrove forests, seagrass meadows, and coral reefs, some of which have not yet recovered, and may never do so. These findings paint a bleak picture, underscoring the need for urgent action.

During this period, which spanned both El Niño and La Niña conditions, scientists around Australia reported the following events:

2011: The most extreme marine heatwave ever occurred off the west coast of Australia. Temperatures were as much as 2-4℃ above average for extended periods and there was coral bleaching along more than 1,000km of coast and loss of kelp forest along hundreds of kilometres.

Seagrasses in Shark Bay and along the entire east coast of Queensland were also severely affected by extreme flooding and cyclones. The loss of seagrasses in Queensland may have led to a spike in deaths of turtles and dugongs.

2013: Extensive coral bleaching took place along more than 300km of the Pilbara coast of northwestern Australia.

2016: The most extreme coral bleaching ever recorded on the Great Barrier Reef affected more than 1,000km of the northern Great Barrier Reef. Mangrove forests across northern Australia were killed by a combination of drought, heat and abnormally low sea levels along the coast of the Gulf of Carpentaria across the Northern Territory and into Western Australia.

2017: An unprecedented second consecutive summer of coral bleaching on the Great Barrier Reef affects northern Great Barrier Reef again, as well as parts of the reef further to the south.

Heritage areas affected

Many of the impacted areas are globally significant for their size and biodiversity, and because until now they have been relatively undisturbed by climate change. Some of the areas affected are also World Heritage Areas (Great Barrier Reef, Shark Bay, Ningaloo Coast).

Seagrass meadows in Shark Bay are among the world’s most lush and extensive and help lock large amounts of carbon into sediments. The left image shows healthy seagrass but the right image shows damage from extreme climate events in 2011.
Mat Vanderklift, Author provided

The habitats affected are “foundational”: they provide food and shelter to a huge range of species. Many of the animals affected – such as large fish and turtles – support commercial industries such as tourism and fishing, as well as being culturally important to Australians.

Recovery across these impacted habitats has begun, but it’s likely some areas will never return to their previous condition.

We have used ecosystem models to evaluate the likely long-term outcomes from extreme climate events predicted to become more frequent and more intense.

This work suggests that even in places where recovery starts, the average time for full recovery may be around 15 years. Large slow-growing species such as sharks and dugongs could take even longer, up to 60 years.

But extreme climate events are predicted to occur less than 15 years apart. This will result in a step-by-step decline in the condition of these ecosystems, as it leaves too little time between events for full recovery.

This already appears to be happening with the corals of the Great Barrier Reef.

Gradual decline as things get warmer

Damage from extreme climate events occurs on top of more gradual changes driven by increases in average temperature, such as loss of kelp forests on the southeast coasts of Australia due to the spread of sea urchins and tropical grazing fish species.

Ultimately, we need to slow down and stop the heating of our planet due to the release of greenhouse gases. But even with immediate and effective emissions reduction, the planet will remain warmer, and extreme climatic events more prevalent, for decades to come.

Recovery might still be possible, but we need to know more about recovery rates and what factors promote recovery. This information will allow us to give the ecosystems a helping hand through active restoration and rehabilitation efforts.




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We will need new ways to help ecosystems function and to deliver the services that we all depend on. This will likely include decreasing (or ideally, stopping) direct human impacts, and actively assisting recovery and restoring damaged ecosystems.

Several such programs are active around Australia and internationally, attempting to boost the ability of corals, seagrass, mangroves and kelp to recover.

But they will need to be massively scaled up to be effective in the context of the large scale disturbances seen in this decade.The Conversation

Mangroves at the Flinders River near Karumba in the Gulf of Carpentaria. The healthy mangrove forest (left) is near the river while the dead mangroves (right) are at higher levels where they were much more stressed by conditions in 2016. Some small surviving mangroves are seen beginning to recover by 2017.
Robert Kenyon, Author provided

Russ Babcock, Senior Principal Research Scientist, CSIRO; Anthony Richardson, Professor, The University of Queensland; Beth Fulton, CSIRO Research Group Leader Ecosystem Modelling and Risk Assessment, CSIRO; Eva Plaganyi, Senior Principal Research Scientist, CSIRO, and Rodrigo Bustamante, Research Group Leader , CSIRO

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

Protecting wetlands helps communities reduce damage from hurricanes and storms



File 20181009 72133 1o1hr7u.jpg?ixlib=rb 1.1
Protecting coastal wetlands, like this slough in Florida’s Everglades National Park, is a cost-effective way to reduce flooding and storm damage.
NPS/C. Rivas

Siddharth Narayan, University of California, Santa Cruz and Michael Beck, University of California, Santa Cruz

2017 was the worst year on record for hurricane damage in Texas, Florida and the Caribbean from Harvey, Irma and Maria. We had hoped for a reprieve this year, but less than a month after Hurricane Florence devastated communities across the Carolinas, Hurricane Michael has struck Florida.

Coastlines are being developed rapidly and intensely in the United States and worldwide. The population of central and south Florida, for example, has grown by 6 million since 1990. Many of these cities and towns face the brunt of damage from hurricanes. In addition, rapid coastal development is destroying natural ecosystems like marshes, mangroves, oyster reefs and coral reefs – resources that help protect us from catastrophes.

In a unique partnership funded by Lloyd’s of London, we worked with colleagues in academia, environmental organizations and the insurance industry to calculate the financial benefits that coastal wetlands provide by reducing storm surge damages from hurricanes. Our study, published in 2017, found that this function is enormously valuable to local communities. It offers new evidence that protecting natural ecosystems is an effective way to reduce risks from coastal storms and flooding.

Coastal wetlands and flood damage reduction: A collaboration between academia, conservation and the risk industry.

The economic value of flood protection from wetlands

Although there is broad understanding that wetlands can protect coastlines, researchers have not explicitly measured how and where these benefits translate into dollar values in terms of reduced risks to people and property. To answer this question, our group worked with experts who understand risk best: insurers and risk modelers.

Using the industry’s storm surge models, we compared the flooding and property damages that occurred with wetlands present during Hurricane Sandy to the damages that would have occurred if these wetlands were lost. First we compared the extent and severity of flooding during Sandy to the flooding that would have happened in a scenario where all coastal wetlands were lost. Then, using high-resolution data on assets in the flooded locations, we measured the property damages for both simulations. The difference in damages – with wetlands and without – gave us an estimate of damages avoided due to the presence of these ecosystems.

Our paper shows that during Hurricane Sandy in 2012, coastal wetlands prevented more than US$625 million in direct property damages by buffering coasts against its storm surge. Across 12 coastal states from Maine to North Carolina, wetlands and marshes reduced damages by an average of 11 percent.

These benefits varied widely by location at the local and state level. In Maryland, wetlands reduced damages by 30 percent. In highly urban areas like New York and New Jersey, they provided hundreds of millions of dollars in flood protection.

Wetland benefits for flood damage reduction during Sandy (redder areas benefited more from having wetlands).
Narayan et al., Nature Scientific Reports 7, 9463 (2017)., CC BY

Wetlands reduced damages in most locations, but not everywhere. In some parts of North Carolina and the Chesapeake Bay, wetlands redirected the surge in ways that protected properties directly behind them, but caused greater flooding to other properties, mainly in front of the marshes. Just as we would not build in front of a seawall or a levee, it is important to be aware of the impacts of building near wetlands.

Wetlands reduce flood losses from storms every year, not just during single catastrophic events. We examined the effects of marshes across 2,000 storms in Barnegat Bay, New Jersey. These marshes reduced flood losses annually by an average of 16 percent, and up to 70 percent in some locations.

Reductions in annual flood losses to properties that have a marsh in front (blue) versus properties that have lost the marshes in front (orange).
Narayan et al., Nature Scientific Reports 7, 9463 (2017)., CC BY

In related research, our team has also shown that coastal ecosystems can be highly cost-effective for risk reduction and adaptation along the U.S. Gulf Coast, particularly as part of a portfolio of green (natural) and gray (engineered) solutions.

Reducing risk through conservation

Our research shows that we can measure the reduction in flood risks that coastal ecosystems provide. This is a central concern for the risk and insurance industry and for coastal managers. We have shown that these risk reduction benefits are significant, and that there is a strong case for conserving and protecting our coastal ecosystems.

The next step is to use these benefits to create incentives for wetland conservation and restoration. Homeowners and municipalities could receive reductions on insurance premiums for managing wetlands. Post-storm spending should include more support for this natural infrastructure. And new financial tools such as resilience bonds, which provide incentives for investing in measures that reduce risk, could support wetland restoration efforts too.

The dense vegetation and shallow waters within wetlands can slow the advance of storm surge and dissipate wave energy.
USACE

Improving long-term resilience

Increasingly, communities are also beginning to consider ways to improve long-term resilience as they assess their recovery options.

There is often a strong desire to return to the status quo after a disaster. More often than not, this means rebuilding seawalls and concrete barriers. But these structures are expensive, will need constant upgrades as as sea levels rise, and can damage coastal ecosystems.

Even after suffering years of damage, Florida’s mangrove wetlands and coral reefs play crucial roles in protecting the state from hurricane surges and waves. And yet, over the last six decades urban development has eliminated half of Florida’s historic mangrove habitat. Losses are still occurring across the state from the Keys to Tampa Bay and Miami.

Protecting and nurturing these natural first lines of defense could help Florida homeowners reduce property damage during future storms. In the past two years our team has worked with the private sector and government agencies to help translate these risk reduction benefits into action for rebuilding natural defenses.

Across the United States, the Caribbean and Southeast Asia, coastal communities face a crucial question: Can they rebuild in ways that make them better prepared for the next storm, while also conserving the natural resources that make these locations so valuable? Our work shows that the answer is yes.

This is an updated version of an article originally published on Sept. 25, 2017.The Conversation

Siddharth Narayan, Postdoctoral Fellow, Coastal Flood Risk, University of California, Santa Cruz and Michael Beck, Research professor, University of California, Santa Cruz

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

Desal plants might do less damage to marine environments than we thought



File 20180920 10496 zlu726.jpg?ixlib=rb 1.1
Some sea creatures are displaced by the desalination plant, but others actually grow.
Supplied

Graeme Clark, UNSW and Emma Johnston, UNSW

Millions of people all over the world rely on desalinated water. Closer to home, Australia has desalination plants in Melbourne, Adelaide, Perth, the Gold Coast, and many remote and regional locations.

But despite the growing size and number of desalination plants, the environmental impacts are little understood. Our six-year study, published recently in the journal Water Research, looked at the health the marine environment before, during and after the Sydney Desalination Plant was operating.




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Our research tested the effect of pumping and “diffusing” highly concentrated salt water (a byproduct of desalination) back into the ocean.

Contrary to our expectation that high salt levels would impact sea creatures, we found that ecological changes were largely confined to an area within 100m of the discharge point, and reduced shortly after the plant was turned off. We also found the changes were likely a result of strong currents created by the outfall jets, rather than high salinity.

Desalination is growing

We examined six underwater locations at about 25m depth over a six-year period during which the plant was under construction, then operating, and then idle. This let us rigorously monitor impacts to and recovery of marine life from the effects of pumping large volumes of hypersaline water back into the ocean. We tested for impacts and recovery at two distances (30m and 100m) from the outfall.

This study provides the first before-and-after test of ecological impacts of desalination brine on marine communities, and a rare insight into mechanisms behind the potential impacts of a growing form of human disturbance.

About 1% of the world’s population now depends on desalinated water for daily use, supplied by almost 20,000 desalination plants that produce more than 90 million cubic meters of water per day.

Increasingly frequent and severe water shortages are projected to accelerate the growth in desalination around the world. By 2025, more than 2.8 billion people in 48 countries are likely to experience water scarcity, with desalination expected to become an increasingly crucial water source for many coastal populations.

Effect of the diffusers

The diffusers that pump concentrated salt water into the ocean at a high velocity (to increase dilution) are so effective that salinity was almost at background levels within 100m of the outfall. However, the diffusion process increased the speed of currents close to the outfall.

This strong current affects species differently, depending on how they settle and feed. Marine species with strong swimming larvae, such as barnacles, can easily settle in high flow and then benefit from faster delivery of food particles. These animals increased in number and size near the outfall. In contrast, species with slow swimming larvae, such as tubeworms, lace corals and sponges, prefer settling and feeding in low current and became less abundant near the outfall.

Therefore, the high-pressure diffusers designed to reduce hypersalinity may have inadvertently caused impacts due to flow. However, these ecological changes may be less concerning than those caused by hypersalinity, as the currents were still within the range that marine communities experience naturally.

Our findings are important, because as drought conditions around the nation worsen and domestic water supplies are coming under strain, desalination is starting to ramp up in eastern and southern Australia.

For instance, water levels at Sydney’s primary dam at Warragamba have dropped to around 65% and the desalination plant is contracted to start supplying drinking water back into the system when dam levels fall below 60%. This plant can potentially double in capacity if needed.




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There is a rapid expansion of the use of desalination, with global capacity increasing by 57% between 2008 and 2013. Our results will help designers and researchers in this area ensure desalination plants minimise their effect on local coastal systems.The Conversation

Graeme Clark, Senior Research Associate in Ecology, UNSW and Emma Johnston, Professor and Dean of Science, UNSW

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

Banning fishing has helped parts of the Great Barrier Reef recover from damage


Camille Mellin, Australian Institute of Marine Science; Aaron MacNeil, Australian Institute of Marine Science, and Julian Caley, Australian Institute of Marine Science

The world’s coral reefs face unprecedented threats. Their survival depends on how well they can cope with a long list of pressures including fishing, storms, coral bleaching, outbreaks of coral predators and reduced water quality. Together, these disturbances have caused the Great Barrier Reef to lose half of its coral cover since 1985.

One often-used way of protecting marine ecosystems is to close parts of the ocean to fishing, in no-take marine reserves. From research, we know that by reducing fishing you end up with more and bigger fish (and other harvested species such as lobsters).

But other benefits of protection might be more surprising. In a new study, we show that no-take reserves helped the Great Barrier Reef’s corals to resist a range of disturbances, such as bleaching, disease and crown-of-thorns starfish, and to recover more quickly from damage.

More exposure, but better protection

Our study used observations between 1993 and 2013 of 34 types of coral and invertebrates and 215 fish species on 46 reefs spread across the Great Barrier Reef. Among the 46 study reefs, 26 were open to fishing and 20 were in no-take marine reserves.

During the study period, several occurrences of coral bleaching, coral disease, storms and outbreaks of crown-of-thorns starfish were recorded.

The total number of disturbances affecting our study reefs increased in recent years (2010-12), mostly due to severe storms affecting the central and southern sections of the Great Barrier Reef. Among our study reefs, those located inside no-take marine reserves were more exposed to disturbance than those outside no-take marine reserves.

Our study showed that, inside no-take marine reserves, the impact of disturbance was reduced by 38% for fish and by 25% for corals compared with unprotected reefs. This means that no-take marine reserves benefit not only fish but entire reef communities, including corals, and might help to slow down the rapid degradation of coral reefs.

Damaged coral reef around Lizard Island a few days after cyclone Ita.
Photo by Tom Bridge, http://www.tethys-images.com

Faster recovery

In addition to greater resistance, reef organisms recovered more quickly from disturbance inside no-take marine reserves. After each disturbance, we measured the time that both coral and fish communities took to return to their pre-disturbance state.

We found coral communities took the longest to recover after crown-of-thorns starfish outbreaks. Outside no-take marine reserves, it took on average nine years for these communities to recover. It took just over six years inside no-take marine reserves.

Although there is more work to be done, one reason that reefs inside no-take zones are able to cope better with disturbances is that they preserve and promote a wider range of important ecological functions. Where fishing reduces the numbers of some species outside protected areas, some of these functions could be lost.

Coral reef showing signs of recovery.
Photo copyright Tom Bridge/www.tethys-images.com

Knowledge for conservation

Marine reserves (including no-take zones) currently cover 3.4% of the world’s ocean, which is still well below the 10% target for 2020 recommended by the Convention on Biological Diversity. The slow progress towards this target is partly due to the perceived high costs of protection compared to true ecological benefits, which can be difficult to gauge. While some surprising benefits are beginning to be revealed in studies like ours, such benefits remain little understood.

Our results help to fill that gap by showing that no-take marine reserves can boost both the resistance and recovery of reef communities following disturbance. In ecology, resistance plus recovery equals resilience.

Our work suggests that the net benefit of no-take marine reserves is much greater than previously thought. No-take marine reserves host not only more and bigger fishes, but more resilient communities that might decline at slower rates.

These results reinforce the idea that no-take marine reserves should be widely implemented and supported as a means of maintaining the integrity of coral reefs globally.

Our conclusions also demonstrate that we need long-term monitoring programs which provide a unique opportunity to assess the sustained benefits of protection.

The Conversation

Camille Mellin, Research Scientist, Australian Institute of Marine Science; Aaron MacNeil, Senior Research Scientist, Australian Institute of Marine Science, and Julian Caley, Senior Principal Research Scientist, Australian Institute of Marine Science

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

Australia: New South Wales – Sugarloaf State Conservation Area Mining Damage


The link below is to an article reporting on the mine subsidence disaster in the Sugarloaf State Conservation Area of New South Wales, Australia.

For more visit:
http://www.theherald.com.au/story/1743298/mine-subsidence-rehab-credibility-mess-video/

Media Release: Stockton Bight


The link below is to a media release concerning damage to a midden at Stockton Bight in New South Wales, Australia.

For more visit:
http://www.environment.nsw.gov.au/media/OEHmedia13080101.htm

Media Release: Wollumbin National Park


The link below is to a media release concerning the summit track at Wollumbin National Park, which was closed following extensive damage by ex-tropical cyclone Oswald in January 2013.

For more visit:
http://www.environment.nsw.gov.au/media/OEHmedia13053002.htm