Climate change may change the way ocean waves impact 50% of the world’s coastlines


Mark Hemer, CSIRO; Ian Young, University of Melbourne; Joao Morim Nascimento, Griffith University, and Nobuhito Mori, Kyoto University

The rise in sea levels is not the only way climate change will affect the coasts. Our research, published today in Nature Climate Change, found a warming planet will also alter ocean waves along more than 50% of the world’s coastlines.

If the climate warms by more than 2℃ beyond pre-industrial levels, southern Australia is likely to see longer, more southerly waves that could alter the stability of the coastline.

Scientists look at the way waves have shaped our coasts – forming beaches, spits, lagoons and sea caves – to work out how the coast looked in the past. This is our guide to understanding past sea levels.




Read more:
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But often this research assumes that while sea levels might change, wave conditions have stayed the same. This same assumption is used when considering how climate change will influence future coastlines – future sea-level rise is considered, but the effect of future change on waves, which shape the coastline, is overlooked.

Changing waves

Waves are generated by surface winds. Our changing climate will drive changes in wind patterns around the globe (and in turn alter rain patterns, for example by changing El Niño and La Niña patterns). Similarly, these changes in winds will alter global ocean wave conditions.




Read more:
Curious Kids: why are there waves?


Further to these “weather-driven” changes in waves, sea level rise can change how waves travel from deep to shallow water, as can other changes in coastal depths, such as affected reef systems.

Recent research analysed 33 years of wind and wave records from satellite measurements, and found average wind speeds have risen by 1.5 metres per second, and wave heights are up by 30cm – an 8% and 5% increase, respectively, over this relatively short historical record.

These changes were most pronounced in the Southern Ocean, which is important as waves generated in the Southern Ocean travel into all ocean basins as long swells, as far north as the latitude of San Francisco.

Sea level rise is only half the story

Given these historical changes in ocean wave conditions, we were interested in how projected future changes in atmospheric circulation, in a warmer climate, would alter wave conditions around the world.

As part of the Coordinated Ocean Wave Climate Project, ten research organisations combined to look at a range of different global wave models in a variety of future climate scenarios, to determine how waves might change in the future.

While we identified some differences between different studies, we found if the 2℃ Paris agreement target is kept, changes in wave patterns are likely to stay inside natural climate variability.

However in a business-as-usual climate, where warming continues in line with current trends, the models agreed we’re likely to see significant changes in wave conditions along 50% of the world’s coasts. These changes varied by region.

Less than 5% of the global coastline is at risk of seeing increasing wave heights. These include the southern coasts of Australia, and segments of the Pacific coast of South and Central America.

On the other hand decreases in wave heights, forecast for about 15% of the world’s coasts, can also alter coastal systems.

But describing waves by height only is the equivalent of describing an orchestra simply by the volume at which it plays.

Some areas will see the height of waves remain the same, but their length or frequency change. This can result in more force exerted on the coast (or coastal infrastructure), perhaps seeing waves run further up a beach and increasing wave-driven flooding.

Similarly, waves travelling from a slightly altered direction (suggested to occur over 20% of global coasts) can change how much sand they shunt along the coast – important considerations for how the coast might respond. Infrastructure built on the coast, or offshore, is sensitive to these many characteristics of waves.

While each of these wave characteristics is important on its own, our research identified that about 40% of the world’s coastlines are likely to see changes in wave height, period and direction happening simultaneously.

While some readers may see intense waves offering some benefit to their next surf holiday, there are much greater implications for our coastal and offshore environments. Flooding from rising sea levels could cost US$14 trillion worldwide annually by 2100 if we miss the target of 2℃ warming.




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How coastlines respond to future climate change will be a response to a complex interplay of many processes, many of which respond to variable and changing climate. To focus on sea level rise alone, and overlooking the role waves play in shaping our coasts, is a simplification which has great potential to be costly.


The authors would like to acknowledge the contribution of Xiaolan Wang, Senior Research Scientist at Environment and Climate Change, Canada, to this article.The Conversation

Mark Hemer, Principal Research Scientist, Oceans and Atmosphere, CSIRO; Ian Young, Kernot Professor of Engineering, University of Melbourne; Joao Morim Nascimento, PhD Candidate, Griffith University, and Nobuhito Mori, Professor, Kyoto University

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

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Cleaning up runoff onto the Great Barrier Reef: how art and science are inspiring farmers to help


Sarah Hamylton, University of Wollongong and Lucas Ihlein, University of Wollongong

The most recent report card on the Great Barrier Reef’s water quality highlighted major changes that need to be made to meet targets by 2018. Sediment and pollutant runoff from land use have increased 2-3 fold since 1850, largely driven by agricultural land clearing and grazing, while fertiliser used in sugar cane farming contributes to nitrogen runoff.

Runoff increases coral’s sensitivity to bleaching and disease, shifts the balance between coral and algae, leads to a build-up of pollutants in marine species that are long-lived or high in the food web, and increases the chances of crown-of-thorns starfish outbreaks.

Improving water quality will likely increase the health of reef organisms, and help reefs to bounce back from disturbances.

Government investment plans need to account properly for the total estimated value of the Great Barrier Reef and past progress in reducing runoff. An estimated A$500 million per year is needed to improve management action.

So what’s the best way to meet these targets? You won’t be surprised to find that scientists are working on the answer. But innovative projects fusing art and science are also appearing in north Queensland.

The problem of collective action

Like many environmental issues, runoff on the Great Barrier Reef is a classic example of a collective action problem. Collective action is at the heart of this issue in two ways.

First, the alongshore transport of sediment and runoff pollutants by currents means that the effects of managing runoff along one section of coastline may be felt elsewhere. The condition of the reef adjacent to a particular river mouth may not, therefore, necessarily reflect the land management within that river’s catchment.

Second, the health of the reef is dependent on other factors, such as bleaching driven by increased sea surface temperatures related to climate change. These are caused by many geographically remote activities (for instance, someone burning coal in London).

Collective action problems can be understood through US academic Garret Hardin’s famous “tragedy of the commons” theory. This theory states that self-interested individuals acting rationally may not behave in the best interests of the whole group.

Hardin used the example of a group of herdsmen allowing their cattle to graze a pasture that is running out of fodder. For an individual herdsman, the cost of removing cattle exceeds the benefit of leaving some pasture for the future, unless other herdsmen also agree to remove cattle.

Similarly, it takes an exceptional individual to reduce their runoff impacts, in light of the agricultural benefits to be gained from activities that increase runoff volume and decrease its quality (such as land clearing and use of fertilizers). This is particularly the case when others are not acting to abate their own activities.

Many farmers say that the Reef 2050 target to reduce runoff by 80% by 2025 is not economically viable. But without acting now, our metaphorical common (the inshore Great Barrier Reef) will continue to degrade.

Best environmental practice

Agriculture is a social and cultural activity, just as much as it is a process of environmental engineering, and the push to transform farming practices needs to recognise this. Top down incentive schemes do have some impact, but could there be a better way?

For instance, for sugar cane growers, the Smartcane Best Management Practice (BMP) Guidelines are an attempt by the industry to shift farming practices towards compliance with government directives to reduce run-off impacts on the reef.

The Smartcane BMP guidelines aim to improve farming practices through seven principles:

  1. Soil health and plant nutrition management

  2. Pest, disease and weed management

  3. Drainage and irrigation management

  4. Crop production and harvest management

  5. Natural systems management

  6. Farm business management

  7. Workplace health and safety management

As with many corporate social responsibility initiatives, growers who volunteer for Smartcane BMP are required to assess their current practices and set benchmarks for improvement in order to receive accreditation that indicates good environmental practice. There are clear marketing and, in many cases, cost-cutting benefits that motivate farmers to participate.

This has driven some examples of good practice within the farming community. However, as the 2015 report card shows, “only 23% of sugarcane land was managed using best management practice systems”, which is inadequate for achieving the Reef 2050 goal of an 80% reduction in dissolved nitrogen loads from agricultural runoff by 2025.

Motivating farmers

One project which engages with this problem is Sugar vs the Reef? by artists Lucas Ihlein, Kim Williams and Ian Milliss. This project is based on the idea that there is a greater chance of influencing farming practices if the desire to improve environmental performance comes from within the farming community. Innovation is celebrated from below by staging public collaborative events to generate dialogue about agriculture’s complex social and environmental interactions.

Innovative Mackay farmers Simon Mattsson and Allan Maclean in a dual crop of sugar cane and sunflowers. The sunflowers shade out weeds, break the sugarcane monocrop by diversifying soil biology, and attract a lot of attention, triggering public discussions about the crucial role of soil health in reducing runoff to the Great Barrier Reef.
Photo by Lucas Ihlein

For example, over the next two years, the project will coordinate a collaboration between Mackay Botanical Gardens, sugar cane farmers and community members to plant a dual crop of sunflowers and sugar cane as a highly visible work of “land art”.

This crop – whose cycle of planting, growth and harvesting will exceed the minimum standards of BMP – will stretch over four hectares near the centre of Mackay. Over two years, the project will engage sugarcane farmers, artists, high school students, members of the Australian South Sea Islander community, the Greater Whitsunday Food Network, soil and reef scientists, as well as the Great Barrier Reef Marine Park Authority.

While it is easy to point the finger at agricultural practices as a major cause of poor water quality in the inner waters of the Great Barrier Reef, change will be slow until the complex social factors that shape modern farming are recognised. This requires deeper engagement with the varied cultures of farming.

The Conversation

Sarah Hamylton, Senior Lecturer, School of Earth and Environmental Sciences, University of Wollongong and Lucas Ihlein, ARC DECRA Research Fellow, University of Wollongong

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

Coastal communities, including 24 federal seats at risk, demand action on climate threats


Barbara Norman, University of Canberra

Representatives of Australian coastal communities have gathered this week to discuss the major challenges they face. Delegates at the conference in Rockingham, Western Australia, represent 40 councils around Australia, some falling within the 24 federal electorates held by a margin of 5% or less. In contrast to the federal budget, climate change is at the top of their agenda.

At the coming federal election, 24 coastal electorates are held by a margin of 5% or less.
Compiled with NATSEM, University of Canberra and the Australian Coastal Councils, Author provided

Sea-level rise, floods, storms and bushfire were common concerns. The Australian Coastal Councils Conference’s May 6 communique demands national action:

Coastal councils and their communities call on the Australian Government to play a leadership role in developing a co-ordinated national approach to coastal management by adopting a set of policy initiatives based on the recommendations of the bipartisan Australian Parliamentary Coastal Inquiry.

Challenges of growth and change

Australia’s population is set to grow from 24 million to 40 million people by 2050. On present trends, this growth is likely to be concentrated in coastal regions, mostly along the eastern seaboard.

Australian Coastal Councils Association chair Barry Sammels, the mayor of Rockingham, observed:

Coastal seats are among the most vulnerable at the forthcoming election. Some of them are growing very rapidly, and others are changing demographically as ‘sea-changers’ migrate to coastal areas and people with young families are relocating from the cities in search of a better quality of life. This invariably means these regional coastal electorates, which have traditionally elected conservative political candidates, are becoming politically more volatile.

These communities are “at the forefront of climate vulnerability”, Sammels said. They are already dealing with coastal erosion and the prospect of rising sea levels and more frequent and extreme weather events.

Coastal communities, in particular those which are changing in character, are demanding these risks be taken seriously. … They currently feel there is a lack of commitment from both major parties to deal with these threats.

Lack of urgency at the top

Population growth is concentrated in coastal centres vulnerable to climate change.
p.16 State of Australian Cities 2014-15, Australian Government

While bipartisan interest in cities policies is growing, this needs to be extended to coastal regions experiencing big changes on several fronts – demographic, economic and environmental.

The lack of long-term strategic coastal planning puts both communities and environments at risk. The bleaching of the Great Barrier Reef illustrates the impacts of environmental change on tourism, jobs and long-term economic security.

We need a national plan to support local councils to better manage coastal urban development, climate change and the consequences for their communities. We have had over 25 national reports leading to largely no action.

In the communique, coastal councils reasonably call for action on key recommendations of the comprehensive 2009 parliamentary inquiry:

We propose that the following recommendations of the coastal inquiry be adopted:
That the Australian Government, in co-operation with state, territory and local governments, and in consultation with coastal stakeholders, develop an Intergovernmental Agreement on the Coastal Zone to be endorsed by the Council of Australian Governments.

And that:

The Australian Government ensure that [the agreement] forms the basis for a National Coastal Zone Policy and Strategy, which should set out the principles, objectives and actions that must be taken to address the challenges of integrated coastal zone management for Australia.

Despite much-reduced federal funding, the National Climate Change Adaptation Facility continues to help inform action by local government. Clearly, however, better long-term planning is required. This requires deeper institutional support, including a national perspective on urban growth in the context of climate change.

Mandurah, WA, epitomises both the pace of growth of coastal communities and their vulnerability to climate change.
Rexness/flickr, CC BY-SA

Action has begun locally

Finally, not all coastal planning and management is achieved through law and policy. A great deal of activity occurs locally through goodwill and collaboration. To highlight three examples:

Such collaboration and innovation deserves long-term funding from higher levels of government.

We may have got this far without an integrated approach to coastal planning and management, but without it there is no way we will be able to manage coastal growth with the projected demographic, economic and climate changes.

That’s why local councils are demanding immediate action on a national coastal policy to meet the needs of our coastal communities and environment. To ignore their call is a very significant political risk indeed.

The Conversation

Barbara Norman, Chair of Urban & Regional Planning & Director of Canberra Urban & Regional Futures, University of Canberra

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

Coral Reefs and Shoreline Protection


The link below is to an article that takes a look at coral reefs and the part they play in protection shorelines from surf erosion.

For more visit:
http://thinkprogress.org/climate/2014/05/16/3438478/coral-reefs-protect-shorelines/

The Six Big Environment Issues of Our Day


The link below is to an article that takes a look at the six big environmental issues of our day – climate change, loss of biodiversity, erosion, water scarcity, deforestation and pollution.

For more visit:
http://inhabitat.com/top-6-environmental-issues-for-earth-day-and-what-you-can-do-to-solve-them/