Air guns used for marine oil and gas exploration are loud enough to affect humpback whales up to 3km away, potentially affecting their migration patterns, according to our new research.
Whales’ communication depends on loud sounds, which can travel very efficiently over distances of tens of kilometres in the underwater environment. But our study, published today in the Journal of Experimental Biology, shows that they are affected by other loud ocean noises produced by humans.
As part of the BRAHSS (Behavioural Response of Humpback whales to Seismic Surveys) project, we and our colleagues measured humpback whales’ behavioural responses to air guns like those used in seismic surveys carried out by the offshore mining industry.
Air guns are devices towed behind seismic survey ships that rapidly release compressed air into the ocean, producing a loud bang. The sound travels through the water and into the sea bed, bouncing off various layers of rock, oil or gas. The faint echoes are picked up by sensors towed by the same vessel.
During surveys, the air guns are fired every 10-15 seconds to develop a detailed geological picture of the ocean floor in the area. Although they are not intended to harm whales, there has been concern for many years about the potential impacts of these loud, frequent sounds.
Although it sounds like a simple experiment to expose whales to air guns and see what they do, it is logistically difficult. For one thing, the whales may respond to the presence of the ship towing the air guns, rather than the air guns themselves. Another problem is that humpback whales tend to show a lot of natural behavioural variability, making it difficult to tease out the effect of the air gun and ship.
There is also the question of whether any response by the whales is influenced more by the loudness of the air gun, or how close the air blast is to the whale (although obviously the two are linked). Previous studies have assumed that the response is driven primarily by loudness, but we also looked at the effect of proximity.
We used a small air gun and a cluster of guns, towed behind a vessel through the migratory path of more than 120 groups of humpback whales off Queensland’s sunshine coast. By having two different sources, one louder than the other, we were able to fire air blasts of different perceived loudness from the same distance.
We found that whales slowed their migratory speed and deviated around the vessel and the air guns. This response was influenced by a combination of received level and proximity; both were necessary. The whales were affected up to 3km away, at sound levels over 140 decibels, and deviated from their path by about 500 metres. Within this “zone”, whales were more likely to avoid the air guns.
Each tested group moved as one, but our analysis did not include the effects on different group types, such as a female with calf versus a group of adults, for instance.
Our results suggest that when regulating to reduce the impact of loud noise on whale behaviour, we need to take into account not just how loud the noise is, but how far away it is. More research is needed to find out how drastically the whales’ migration routes change as a result of ocean mining noise.
A report released this week by advocacy group Environmental Justice Australia presents a confronting analysis of toxic emissions from Australia’s coal-fired power plants.
The report, which investigated pollutants including fine particles, nitrogen oxides and sulfur dioxide, also highlights our deeply inadequate mercury emissions regulations. In New South Wales the mercury emissions limit is 666 times the US limits, and in Victoria there is no specific mercury limit at all.
This is particularly timely, given that yesterday the Minamata Convention, a United Nations treaty limiting the production and use of mercury, entered into force. Coal-fired power stations and some metal manufacturing are major sources of mercury in our atmosphere, and Australia’s per capita mercury emissions are roughly double the global average.
In fact, Australia is the world’s sixteenth-largest emitter of mercury, and while our government has signed the Minamata convention it has yet to ratify it. According to a 2016 draft impact statement from the Department of Environment and Energy:
Australia’s mercury pollution occurs despite existing regulatory controls, partly because State and Territory laws limit the concentration of mercury in emissions to air […] but there are few incentives to reduce the absolute level of current emissions and releases over time.
Mercury can also enter the atmosphere when biomass is burned (either naturally or by people), but electricity generation and non-ferrous (without iron) metal manufacturing are the major sources of mercury to air in Australia. Electricity generation accounted for 2.8 tonnes of the roughly 18 tonnes emitted in 2015-16.
Mercury in the food web
Mercury is a global pollutant: no matter where it’s emitted, it spreads easily around the world through the atmosphere. In its vaporised form, mercury is largely inert, although inhaling large quantities carries serious health risks. But the health problems really start when mercury enters the food web.
I’ve been involved in research that investigates how mercury moves from the air into the food web of the Southern Ocean. The key is Antartica’s sea ice. Sea salt contains bromine, which builds up on the ice over winter. In spring, when the sun returns, large amounts of bromine is released to the atmosphere and causes dramatically named “bromine explosion events”.
Essentially, very reactive bromine oxide is formed, which then reacts with the elemental mercury in the air. The mercury is then deposited onto the sea ice and ocean, where microbes interact with it, returning some to the atmosphere and methylating the rest.
Once mercury is methylated it can bioaccumulate, and moves up the food chain to apex predators such as tuna – and thence to humans.
As noted by the Australian government in its final impact statement for the Minamata Convention:
Mercury can cause a range of adverse health impacts which include; cognitive impairment (mild mental retardation), permanent damage to the central nervous system, kidney and heart disease, infertility, and respiratory, digestive and immune problems. It is strongly advised that pregnant women, infants, and children in particular avoid exposure.
Australia must do better
A major 2009 study estimated that reducing global mercury emissions would carry an economic benefit of between US$1.8 billion and US$2.22 billion (in 2005 dollars). Since then, the US, the European Union and China have begun using the best available technology to reduce their mercury emissions, but Australia remains far behind.
But it doesn’t have to be. Methods like sulfur scrubbing, which remove fine particles and sulfur dioxide, also can capture mercury. Simply limiting sulfur pollutants of our power stations can dramatically reduce mercury levels.
Ratifying the Minamata Convention will mean the federal government must create a plan to reduce our mercury emissions, with significant health and economic benefits. And because mercury travels around the world, action from Australia wouldn’t just help our region: it would be for the global good.
In an earlier version of this article the standfirst referenced a 2006 study stating Australia is the fifth largest global emitter of mercury. Australia is now 16th globally.
The Commonwealth Bank of Australia has been in the headlines lately for all the wrong reasons. Beyond money-laundering allegations and the announcement that CEO Ian Narev will retire early, the CBA is now also being sued in the Australian Federal Court for misleading shareholders over the risks climate change poses to their business interests.
This case is the first in the world to pursue a bank over failing to report climate change risks. However, it’s building on a trend of similar actions against energy companies in the United States and United Kingdom.
The CBA case was filed on August 8, 2017 by advocacy group Environmental Justice Australia on behalf of two longstanding Commonwealth Bank shareholders. The case argues that climate change creates material financial risks to the bank, its business and customers, and they failed in their duty to disclose those risks to investors.
This represents an important shift. Conventionally, climate change has been treated by reporting companies merely as a matter of corporate social responsibility; now it’s affecting the financial bottom line.
What do banks need to disclose?
When banks invest in projects or lend money to businesses, they have an obligation to investigate and report to shareholders potential problems that may prevent financial success. (Opening a resort in a war zone, for example, is not an attractive proposition.)
However, banks may now have to take into account the risks posed by climate change. Australia’s top four banks are heavily involved in fossil-fuel intensive projects, but as the world moves towards renewable energy those projects may begin to look dubious.
As the G20’s Taskforce on Climate-Related Financial Disclosures recently reported, climate risks can be physical (for instance, when extreme weather events affect property or business operations) or transition risks (the effect of new laws and policies designed to mitigate climate change, or market changes as economies transition to renewable and low-emission technology).
For example, restrictions on coal mining may result in these assets being “stranded,” meaning they become liabilities rather than assets on company balance sheets. Similarly, the rise of renewable energy may reduce the life span, and consequently the value, of conventional power generation assets.
Companies who rely on the exploitation of fossil fuels face increasing transition risks. So too do the banks that lend money to, and invest in, these projects. It is these types of risks that are at issue in the case against CBA.
What did the CBA know about climate risk?
The claim filed by the CBA shareholders alleges the bank has contravened two central provisions of the Corporations Act 2001:
companies must include a financial report within the annual report which gives a “true and fair” view of its financial position and performance, and
companies must include a director’s report that allows shareholders to make an “informed assessment” of the company’s operations, financial position, business strategies and prospects.
The shareholders argue that the CBA knew – or ought to have known – that climate-related risks could seriously disrupt the bank’s performance. Therefore, investors should have been told the CBA’s strategies for managing those risks so they could make an informed decision about their investment.
Read more: We need a Royal Commission into the banks
The claim also zeros in on the lengthy speculation over whether the CBA would finance the controversial Adani Carmichael coal mine in Queensland. (The bank has since ruled out financing the mine.) The shareholders assert that the resulting “controversy and concern” was a major risk to the CBA’s business.
Global litigation trends
While the CBA case represents the first time worldwide that a financial institution has been sued for misleading disclosure of climate risk, the litigation builds on a broader global trend. There have been a number of recent legal actions in the United States, seeking to enforce corporate risk disclosure obligations in relation to climate change:
Energy giant Exxon Mobile is currently under investigation by the Attorneys General of New York and California over the company’s disclosure practices. At the same time, an ongoing shareholder class action alleges that Exxon Mobile failed to disclose internal reports about the risks climate change posed to their oil and gas reserves, and valued those assets artificially high.
Similar pathways are being pursued in the UK, where regulatory complaints have been made about the failure of major oil and gas companies SOCO International and Cairn Energy to disclose climate-related risks, as required by law.
In this context, the CBA case represents a widening of litigation options to include banks, as well as energy companies. It is also the first attempt in Australia to use the courts to clarify how public listed companies should disclose climate risks in their annual reports.
Potential for more litigation
This global trend suggests more companies are likely to face these kinds of lawsuits in the future. Eminent barrister Noel Hutley noted in October 2016 that many prominent Australian companies, including banks that lend to major fossil fuel businesses, are not adequately disclosing climate change risks.
Hutley predicted that it’s likely only a matter of time before we see a company director sued for failing to perceive or react to a forseeable climate-related risk. The CBA case is the first step towards such litigation.