Aussies may scoff at Britain’s idea of a heatwave, but this time it’s the real deal and it’s no laughing matter.
Extreme heat has hit locations throughout the Northern Hemisphere, in places as far apart as Montreal, Glasgow, Tokyo and Lapland. In the past few weeks heat records have tumbled in a wide range of places, most notably:
- a new record high temperature for Africa of 51.3℃ in Algeria
- a record high temperature in Japan of 41.1℃ near Tokyo
- a world record hottest overnight minimum of 42.6℃ in Oman.
Heat has not been the only problem. Much of northern Europe is experiencing a very persistent drought, with little to no measurable rainfall in months. This has caused the normally lush green fields of England and other European countries to turn brown and even reveal previously hidden archaeological monuments.
What’s behind the widespread extreme heat?
The jet stream, a high-altitude band of air that pushes weather systems around at lower altitudes, has been weaker than normal. It has also been positioned unusually far to the north, particularly over Europe. This has kept the low-pressure systems that often drive wind and rain over northern Europe at bay.
The jet stream has remained locked in roughly the same position over the Atlantic Ocean and northern Europe for the past couple of months. This has meant that the same weather types have remained over the same locations most of the time.
Weather is typically more transient than it has been recently. Even when we do have blocking high-pressure systems associated with high temperatures in northern Europe, they don’t normally linger as long as this.
Is it driven by climate change?
Although climatologists have made great strides in recent years in the field of event attribution – identifying the human climate fingerprint on particular extreme weather events – it is hard to quantify the role of climate change in an event that is still unfolding.
Until the final numbers are in we won’t be able to tell just how much climate change has altered the likelihood or intensity of these particular heat extremes.
Having said that, we can use past analyses of extreme heat events, together with future climate change projections, to infer whether climate change is playing a role in these events.
We also know that increasing numbers of hot temperature records are being set, and that the increased probability of hot temperature records can indeed be attributed to the human influence on the climate.
In Europe especially, there is already a large body of literature that has looked at the role of human-caused climate change in heat extremes. In fact, the very first event attribution study, led by Peter Stott from the UK Met Office, found that human-caused climate change had at least doubled the likelihood of the infamous European heatwave of 2003.
For all manner of heat extremes in Europe and elsewhere, including in Japan, a clear and discernible link with climate change has been made.
Research has also shown that heat extremes similar to those witnessed over the past month or two are expected to become more common as global temperatures continue to climb. The world has so far had around 1℃ of global warming above pre-industrial levels, but at the global warming limits proposed in the Paris climate agreement, hot summers like that of 2003 in central Europe would be a common occurrence.
At 2℃ of global warming, the higher of the two Paris targets, 2003-like hot summers would very likely happen in most years.
But summers have always been hot, haven’t they?
For most parts of the world summers have got warmer, and the hottest summer on record is relatively recent – such as 2003 in parts of central Europe and 2010 in much of eastern Europe. One exception is central England, where the hottest summer remains 1976, although it may be challenged this year.
While extreme hot summers and heatwaves did happen in the past, they were less common. One big difference as far as England is concerned is that its extreme 1976 heatwave was a global outlier, whereas this year’s isn’t.
In 1976 northwestern Europe had higher temperature anomalies than almost anywhere else on the globe. In June 2018 the same region was unusually warm, but so was most of the rest of the Northern Hemisphere.
So while the persistent weather patterns are driving much of the extreme heat we’re seeing across the Northern Hemisphere, we know that human-caused climate change is nudging the temperatures up and increasing the odds of new heat extremes.
Nitrogen pollution has significant environmental and human health costs. Yet it is often conflated with other environmental problems, such as climate change, which is exacerbated by nitrous oxide (N₂O) and nitrogen oxides (NOₓ), or particulate smog, to which ammonia (NH₃) also contributes.
One way to understand our nitrogen use is to look at our nitrogen footprint. This is the amount of reactive nitrogen, which is all forms of nitrogen other than inert nitrogen gas, released into the environment from our daily activities that consume resources including food and energy.
Our earlier research showed that Australia has a large nitrogen footprint. At up to 47kg of nitrogen per person each year, Australia is far ahead of the US (28kg per person), the second on the leaderboard of per capita reactive nitrogen emissions. Australians’ large nitrogen footprints are created largely by a diet rich in animal protein and high levels of coal use for energy.
The nitrogen footprint
Our new research, published in the Journal of Cleaner Production, takes this concept further by measuring the nitrogen footprint of an entire institution, in this case the University of Melbourne.
The institutional nitrogen footprint is the sum of individual activities at the workplace and institutional activities, such as powering laboratories and lecture theatres in the case of a university.
We calculated that the university’s annual nitrogen footprint is 139 tonnes of nitrogen. It is mainly attributable to three factors: food (37%), energy use (32%) and transport (28%).
At the university, food plays a dominant role through the meat and dairy consumed. Nitrogen emissions from food occur mainly during its production, whereas emissions from energy use come mainly from coal-powered electricity use and from fuel used during business travel.
We also modelled the steps that the university could take to reduce its nitrogen footprint. We found that it could be reduced by 60% by taking action to cut emissions from the three main contributing factors: food, energy use, and travel.
The good news is if the university implements all the changes to energy use detailed in its Sustainability Plan – which includes strategies such as adopting clean energy (solar and wind), optimising energy use and buying carbon credits – this would also reduce nitrogen pollution by as much as 29%.
Changing habits of air travel and food choices would be a challenge, as this requires altering the behaviour of people from a culture that places tremendous value on travelling and a love for coffee and meat.
Generally, Australians fly a lot compared to the rest of the world, at significant cost to the environment. We could offset the travel, and we do take that possibility into account, but as others have written before us, we should not make the mistake of assuming that emissions offsets make air travel “sustainable”.
The question that perhaps need to be asked, for work travel, is “to travel or not to travel?” Let’s face it, why are so many academic conferences set in idyllic locations, if not to entice us to attend?
Animal products are major contributors to nitrogen emissions, given the inefficiency of conversion from the feed to milk or meat. Would people be willing to change their latte, flat white or cappuccino to a long black, espresso or macchiato? Or a soy latte?
As 96% of the nitrogen emissions occur outside the university’s boundaries, their detrimental effects are invisible to the person on the ground, while the burden of the pollution is often borne far away, both in time and space.
But, as our study shows for the first time, large institutions with lots of staff are well placed to take steps to cut their large nitrogen footprint.
New Zealand could become the first country in the world to put a price on greenhouse gas emissions from agriculture.
Leading up to the 2017 election, the now Prime Minister Jacinda Ardern famously described climate change as “my generation’s nuclear-free moment”. The promised zero carbon bill is now underway, but in an unusual move, many provisions been thrown open to the public in a consultation exercise led by Minister for Climate Change James Shaw.
More than 4,000 submissions have already been made, with a week still to go, and the crunch point is whether or not agriculture should be part of the country’s transition to a low-emission economy.
Zero carbon options
Many of the 16 questions in the consultation document concern the proposed climate change commission and how far its powers should extend. But the most contentious question refers to the definition of what “zero carbon” actually means.
The government has set a net zero carbon target for 2050, but in the consultation it is asking people to pick one of three options:
net zero carbon dioxide – reducing net carbon dioxide emissions to zero by 2050
net zero long-lived gases and stabilised short-lived gases – carbon dioxide and nitrous oxide to net zero by 2050, while stabilising methane
net zero emissions – net zero emissions across all greenhouse gases by 2050
The three main gases of concern are carbon dioxide (long-lived, and mostly produced by burning fossil fuels), nitrous oxide (also long-lived, and mostly produced by synthetic fertilisers and animal manures) and methane (short-lived, and mostly produced by burping cows and sheep). New Zealand’s emissions of these gases in 2016 were 34 million tonnes (Mt), 9Mt, and 34Mt of carbon dioxide equivalent (CO₂e), respectively.
All three options refer to “net” emissions, which means that emissions can be offset by land use changes, primarily carbon stored in trees. In option 1, only carbon dioxide is offset. In option 2, carbon dioxide and nitrous oxide are offset and methane is stabilised. In option 3, all greenhouses gases are offset.
Opposition leader Simon Bridges has declared his support for the establishment of a climate change commission. DairyNZ, an industry body, has appointed 15 dairy farmers as “climate change ambassadors” and has been running a nationwide series of workshops on the role of agricultural emissions.
Earlier this month, Ardern and the Farming Leaders Group (representing most large farming bodies) published a joint statement that the farming sector and the government are committed to working together to achieve net zero emissions from agri-food production by 2050. Not long after, the Climate Leaders Coalition, representing 60 large corporations, announced their support for strong action to reduce emissions and for the zero carbon bill.
However, the devil is in the detail. While option 2 involves stabilising methane emissions, for example, it does not specify at what level or how this would be determined. Former Green Party co-leader Jeanette Fitzsimons has argued that methane emissions need to be cut hard and fast, whereas farming groups would prefer to stabilise emissions at their present levels.
This would be a much less ambitious 2050 target than option 3, potentially leaving the full 34Mt of present methane emissions untouched. Under current international rules, this would amount to an overall reduction in emissions of about 50% on New Zealand’s 1990 levels and would likely be judged insufficient in terms of the Paris climate agreement. This may not be what people thought they were voting for in 2017.
Why we can’t ignore methane
To keep warming below 2℃ above pre-industrial global temperatures, CO₂ emissions will need to fall below zero (that is, into net removals) by the 2050s to 2070s, along with deep reductions of all other greenhouse gases. To stay close to 1.5℃, the more ambitious of the twin Paris goals, CO₂ emissions would need to reach net zero by the 2040s. If net removals cannot be achieved, global CO₂ emissions will need to reach zero sooner.
Therefore, global pressure to reduce agricultural emissions, especially from ruminants, is likely to increase. A recent study found that agriculture is responsible for 26% of human-caused greenhouse emissions, and that meat and dairy provide 18% of calories and 37% of protein, while producing 60% of agriculture’s greenhouse gases.
A new report by Massey University’s Ralph Sims for the UN Global Environment Facility concludes that currently, the global food supply system is not sustainable, and that present policies will not cut agricultural emissions sufficiently to limit global warming to 1.5℃ above pre-industrial levels.
Finding a way forward
Reducing agricultural emissions without reducing stock numbers significantly is difficult. Many options are being explored, from breeding low-emission animals and selecting low-emission feeds to housing animals off-pasture and methane inhibitors and vaccines.
But any of these will face a cost and it is unclear who should pay. Non-agricultural industries, including the fossil fuel sector, are already in New Zealand’s Emissions Trading Scheme (ETS) and would like agriculture to pay for emissions created on the farm. Agricultural industries argue that they should not pay until cost-effective mitigation options are available and their international competitors face a similar cost.
The government has come up with a compromise. Its coalition agreement states that if agriculture were to be included in the ETS, only 5% would enter into the scheme, initially. The amount of money involved here is small – NZ$40 million a year – in an industry with annual export earnings of NZ$20 billion. It would add about 0.17% to the price of whole milk powder and 0.5% to the wholesale price of beef.
However, it would set an important precedent. New Zealand would become the first country in the world to put a price agricultural emissions. Many people hope that the zero carbon bill will represent a turning point. It may even inspire other countries to follow suit.
A new United Nations report on fisheries and climate change shows that Australian marine systems are undergoing rapid environmental change, with some of the largest climate-driven changes in the Southern Hemisphere.
Reports from around the world have found that many fish species are changing their distribution. This movement threatens to disrupt fishing as we know it.
While rapid change is predicted to continue, researchers and managers are working with fishers to ensure a sustainable industry.
Lessons from across the world
Large climate-driven changes in species distribution and abundance are evident around the world. While some species will increase, global models project declining seafood stocks in tropical regions, where people can least afford alternative foods.
The global concern for seafood changes led the UN Food and Agriculture Organisation (FAO) to commission a new report on the impacts of climate change on fisheries and aquaculture. More than 90 experts from some 20 countries contributed, including us.
The report describes many examples of climate-related change. For instance, the northern movement of European mackerel into Icelandic waters has led to conflict with more southerly fishing states, and apparently contributed to Iceland’s exit from negotiations over its prospective European Union membership.
Changes in fish abundance and behaviour can lead to conflicts in harvesting, as occurred in the Maine lobster fishery. Indirect effects of climate change, such as disease outbreaks and algal blooms, have already temporarily closed fisheries in several countries, including the United States and Australia.
All these changes in turn impact the people who depend on fish for food and livelihoods.
Climate change and fisheries in Australia
The Australian chapter summarises the rapid ocean change in our region. Waters off southeastern and southwestern Australia are particular warming hotspots. Even our tropical oceans are warming almost twice as fast as the global average.
More than 100 Australian marine species have already begun to shift their distributions southwards. Marine heatwaves and other extreme events have harmed Australia’s seagrass, kelp forests, mangroves and coral reefs. Australia’s marine ecosystems and commercial fisheries are clearly already being affected by climate change.
In the Australian FAO chapter, we present information from climate sensitivity analysis and ecosystem models to help managers and fishers prepare for change.
We need to preparing climate-ready fisheries, to minimise negative impacts and to make the most of new opportunities that arise.
Experts from around Australia have rated the sensitivity of more than 100 fished species to climate change, based on their life-history traits. They found that 70% of assessed species have moderate to high sensitivity. As a group, invertebrates are the most sensitive, and pelagic fishes (that live in the open ocean sea) the least.
A range of ecosystem models have also been used to explore how future climate change will impact Australia’s fisheries over the next 40 years. While results varied around Australia, a common projection was that ecosystem production will become more variable.
As fish abundance and distribution changes, predation and competition within food webs will be affected. New food webs may form, changing ecosystems in unexpected ways. In some regions (such as southeastern Australia) the ecosystem may eventually shift into a new state that is quite different to today.
How can Australian fisheries respond?
Our ecosystem models indicate that sustainable fisheries are possible, if we’re prepared to make some changes. This finding builds on Australia’s strong record in fisheries management, supported by robust science, which positions it well to cope with the impacts of climate change. Fortunately, less than 15% of Australia’s assessed fisheries are overfished, with an improving trend.
We have identified several actions that can help fisheries adapt to climate change:
- Management plans need to prioritise the most sensitive species and fisheries, and take the easiest actions first, such as changing the timing or location of operations to match changing conditions.
As ecosystem changes span state and national boundaries, greater coordination is needed across all Australian jurisdictions, and between all the users of the marine environment. For example, policy must be developed to deal with fixed fishing zones when species distribution changes.
Fisheries policy, management and assessment methods need to prepare for both long-term changes and extreme events. Australian fisheries have already shifted to more conservative targets which have provided for increased ecological resilience. Additional quota changes may be needed if stock productivity changes.
In areas where climate is changing rapidly, agile management responses will be required so that action can be taken quickly and adjusted when new information becomes available.
Ultimately, we may need to target new species. This means that Australians will have to adapt to buying (and cooking) new types of fish.
Researchers from a range of organisations and agencies around Australia are now tackling these issues, in partnership with the fishing industry, to ensure that coastal towns with vibrant commercial fishing and aquaculture businesses continue to provide sustainable seafood.
Alistair Hobday, Senior Principal Research Scientist – Oceans and Atmosphere, CSIRO; Beth Fulton, CSIRO Research Group Leader Ecosystem Modelling and Risk Assessment, CSIRO, and Gretta Pecl, Professor, ARC Future Fellow & Editor in Chief (Reviews in Fish Biology & Fisheries), University of Tasmania
We’ve arranged to meet in a gravel car park at the foot of Mt Majura, a darkening wedge above us in the dusk. My daughter and I wait in the car. It’s winter. A woman passes along the nearby pavement, guiding her way by torchlight. Canberra’s streets are kept dim, I learned recently, for the sake of astronomers at nearby Mt Stromlo observatory. In the decade I’ve lived here, I’ve had an ambivalent relationship with Canberra, but the idea of a city that strikes bargains with stargazing scientists to restrict light pollution leaking skyward is endearing.
There are other endearing things. One of them is the amount of bushland interspersed throughout the urban landscape. You can be in the middle of suburbia one minute and bushwalking on nearby Black Mountain, Mt Majura or Mt Ainslie ten minutes later. This kind of mixed landscape is ideal for the citizen science project we’re about to launch into this evening, as soon as the co-ordinator of the ACT and Region Frogwatch Program, Anke Maria Hoefer, arrives for our first training session.
The program runs a community-based annual Frog Census framed against a rapid global decline in frog numbers over the past four decades and the extinction of many frog species. The census began in 2002, and the resulting long-term dataset on the abundance and distribution of local frogs has enabled additional research activities including a climate change project. We’ll take part in the latter, which monitors behavioural shifts in frogs through recording their calls at particular sites each week from June until October.
We’re here for a few reasons. One is to get a lived sense of climate change in our immediate urban surroundings. Plus, I want to make a contribution, however small, to the huge dilemma of climate change and its impacts; give my 13-year-old daughter a taste of scientific fieldwork in case it appeals to her; get to know our local surroundings better; and, as a writer, to think about practices that don’t simply observe or contemplate place but also participate in constructive activities at those same locales.
Numerous commentators have observed that the vast and intangible scale of climate change may be an impediment to more people taking action over our warming atmosphere. We know through the science that climate is shaped by the working of the entire planetary system – the earth’s interactive ocean, atmosphere, land and ice systems all linked to human activity. Depending on where you live, (but not in the Pacific Islands, the deltas of Bangladesh, Arctic Canada, or drought-stricken rural Australia), its impacts can seem far-removed from our own lives and the places we know best and care most about. With care, often, comes action. What can seem an amorphous, far-fetched threat is brought closer to home through studies such as Frogwatch.
The project studies the impact of climate change on phenology, or seasonal behaviour. Most frogs only call during the mating season, which is triggered by temperature and rainfall. Different species mate at different times and volunteers record the onset of mating calls from winter breeders (whistling tree frog and common eastern froglet), early and mid-spring breeders (spotted grass frog, plains froglet, striped marsh frog and smooth toadlet), and late spring to summer breeders (eastern banjo frog and Peron’s tree frog).
Frogs are known as an “indicator species” for water quality and local ecosystem health. With their permeable, membranous skin, through which respiratory gases and water can pass, and their shell-less eggs laid in water, they are sensitive to even low concentrations of pollutants in water and soils. In this study, frogs give a different kind of warning – as they begin calling earlier in the season, they reveal and give voice to the warming climate we now all inhabit.
The project is fortunate enough to be able to build upon weekly counts of calling frogs by ecologist Will Osborne during the 1980s and 1990s in the Canberra region. Effects of climate change can be incremental. They can also be non-linear, as scientist Pep Canadell explained to me in a recent interview. “Climate change expresses itself through extremes. It’s not a linear relationship of impacts,” he said.
This mixture of incremental change and unpredictable “expressions” can be difficult to record in the short term. With this in mind, the Frogwatch project builds on Osborne’s historical data along with the Frog Census data to chart changing trends. A preliminary comparison reveals that the breeding season of some local frog species might be commencing up to six weeks earlier than 40 years ago.
A sonic world
Headlights sweep into the car park and Anke Maria arrives with a visiting German student who is also researching frogs. Anke Maria is a whirlwind of talk and activity, honing in on my daughter as we zip our down jackets, pull on beanies and gloves, switch on torches and head up a gravel fire trail toward the first dam, known as FMC200. Only metres later we stop at the base of a narrow drainage gully. It’s been a dry winter, but with a patch of recent rainfall a miniature sump-like drainage area at the base of the gully is alive with frog calls.
“That’s Crinia signifera,” Anke Maria explains, making what seems a perfect imitation of its repetitive call. “How would you describe it?” she asks. My daughter turns to me. The call is repetitive, creaking. We struggle to think of descriptions. It’s like trying to put a flavour into words.
“Who do you think is calling? The male or female?” Anke Maria asks. My daughter pauses, pondering. “The female,” she hazards a guess. “Good try,” says Anke Maria, “but only the male frog calls. Except when the female makes a warning call.” She imitates this staccato warning sound. “And why do you think the males are calling?” Again my daughter pauses to consider.
We continue walking up the gravel slope amid shadowy shapes of eucalypt trees, a tangle of gorse and acacia undergrowth, a row of looming metal electricity pylons strung along the lower contour lines of Mt Majura.
“They could be hungry or they found food,” my daughter replies.
“Good thinking, but they’re calling to attract a girlfriend. And do you know, scientists think that each frog species can only hear the calls of their own species. It’s like tuning into a radio station. There are many different stations, but we can only tune into one at a time. A female whistling tree frog can only hear a male whistling tree frog, a female corroboree frog can only hear a male corroboree frog.”
They recognise the frequency and intensity or pitch of the call, she explains, and also the pattern of the call or its pulse structure. “This helps the female find a mate from their own species and not get confused by other frogs.”
We ponder this sonic world where one species can be deaf to another, turn left down a narrow walking track, torchlight bobbing along with our footsteps, illuminating tussocks of grass, fallen branches, shrubs, stones, until we reach the dam. “This is for you,” Anke Maria passes a thermometer. “You do it,” she tells my daughter. First we record the ambient temperature then my daughter squats at the edge of the water, waving the thermometer gently through the shallows. We note the weather: light cloud cover, low breeze. We estimate the dam’s surface area and depth. Then our small group falls silent as Anke Maria switches on her phone audio-recorder.
For three minutes we hold still and listen. There’s the low hum of the city below, an ambulance siren swells and recedes, distant traffic, the shuffle of our down jackets as we try not to move, someone sniffs in the chill winter air – and the frogs. You can hear them interspersed across space, some close, some farther away, among vegetation rather than water. Because of Anke Maria’s explanation, I understand now these are not call-and-response sounds. They are invitations, serenades, statements of presence, lures. Sometimes the calls come in a cluster, other times at staggered unpredictable intervals. There are at least two species here, I guess. In the distance, a mopoke calls.
When Anke Maria switches off her phone, we relax into movement again. As we walk towards FMC210, our second dam, she tells us we’ve just heard a whistling tree frog (Litoria verreauxii). “How would you describe his call?” Anke Maria asks.
My daughter decides on a stick dragged across a rough, hollow surface. Anke Maria makes the call. Her imitations are pitch perfect, an art form. She will be the one who checks the recordings that non-specialist volunteers send in weekly, uploaded to the Frogwatch website. We will make our guesses at species we’ve heard, but she will verify with her trained ear, a labour-intensive task.
In our information pack is a CD of local frog species. When we get home we lie on the carpet and listen, the house filled with frog noise.
A new frog
A week later, on our first trip into the dark alone, the evening is silvered and rigid with frost, as if everything is held together in some different, more metallic way. It’s three below zero and falling. Our breath steams, our boots crunch, the bush is still. I sense something in a dead tree ahead before I see it, a tawny frogmouth, grey, motionless, an outcropping like a broken limb. We pause several steps away and it regards us, head half swivelled, a little tuft of feathers at the base of its beak.
The following week, on our descent from the dams, once again a frogmouth is in the same tree. A second bird perches a few metres away. They are bound together in some mute, still business. They survey us. We move on with subdued steps. Beyond the birds, the first row of suburban houses begins. We thread our way back to the car with a sense of secrecy and adventure, past back fences, patches of bright window, catching fugitive glimpses of other people’s lives through a half-open door, a crack in a curtain, the blue flicker of TV light.
At the dams we make our recordings. Air temperature, water temperature, ascending over the weeks. On the far side of Mt Majura lies the airport. Often early into a sound recording, a plane takes off, blotting out all other sound. Ecologist Will Osborne tells me he has observed that the aeroplane sound seems to overlap the call parameters (pitch and pulse structure) of the Common Eastern Froglet. Whenever a plane goes over, the froglet stops calling while other species continue – machine and creature competing on the airwaves.
When I upload the recordings, Anke Maria responds and confirms (or not) my guesses at species. You should soon hear Crinia parinsignifera she emails, so keep your ears peeled for a high pitch narky baby cry!
Her enthusiasm is infectious, her aural sketches vivid, memorable. When we hear the new frog, I know exactly what it is. Everyone on the team, each with sites to attend scattered across Canberra, has been waiting for this particular call.
It might show that an early spring breeder is shifting its season into winter. This minor-sounding alteration has a cascade of flow-on effects. Frogs stagger breeding seasons, giving each species its portion of acoustic space to call, breed, then when eggs hatch into tadpoles to feed (a mode of “time sharing” water and its resources). If seasons shift, merge and overlap, competition for resources intensifies, and survival can be jeopardised.
But this year it’s a cold, dry winter. This telling species, Crinia parinsignifera, is calling two weeks later than last year (when it called early). Meanwhile northern Australia is experiencing its warmest July on record. Non-linear. As the monitoring season progresses, dam levels drop. By the end of October, waters have fallen almost silent.
Will Osborne sends an email around, explaining that cold nights and low water levels will make it hard to interpret this season’s counts. “Most species feel insecure about going out onto that exposed mud and trying to find a call site or searching for mates! It will be a big rush when the weather warms and we get good rains – the calling sequence could be condensed this year which will be interesting…”
Many volunteers join Frogwatch because they want to participate in a hands-on, climate change-related study with real life applications. “They highly value the opportunity to be involved in climate change actions,” Anke Maria says. She captures one of the dilemmas of our times. Many people want to take action but are unsure how. As artist Natalie Jeremijenko observed): “What the climate crisis has revealed to us is a secondary, more insidious and more pervasive crisis, which is the crisis of agency, which is what to do.” Citizen science gives volunteers an opportunity to do something.
Studies that chart the impacts of climate change here-and-now disrupt the assumption that effects will occur in a distant future or at some remote geographic location (melting ice caps, apocalyptic cities under 20 metres of water). Instead, they start to build a picture of measurable effects experienced at the current level of 1°C warming above pre-industrial levels – let alone at 2°C or above, which is what we’re committing to based on current emissions rates. In the Canberra region alone, studies are being conducted into impacts of global warming on urban lizard species (who reside next to the local DFO) and alpine pygmy possums.
At a broader scale, Pep Canadell has observed major ecological transformation in Australia that occurred with a 1.2°C increase during the last El Niño. He calls the El Niños a “window into the future because they bring all this heat and put the world where it may be in 30 or 20 years’ time.”
In the last big El Niño of 2015-16, this “future now” included the well-known bleaching of the coral reef, and fires in the moist peats of alpine Tasmania. There are no records for the past 8,000 years that there has ever been a fire in this part of the world. In addition to these well publicised events, around 700 km of mangroves lining the Gulf of Carpentaria died in a month; and the Murray Darling River had one of its worst algal blooms caused by an algae that belonged not in this region but to hotter places in Queensland.
“These ecological signs are unprecedented, all in this little window of a warmer world that the El Niño brought for us,” said Canadell during our interview. He went on to list even more signs. “For some reason these things don’t go through the media enough because of … whatever,” he added.
The Frogwatch project enables volunteers to dwell in an everyday way with such dispersed ecological signals, which, connected together with other studies, provide a larger picture of both current and future impacts. Volunteers are privileged to make their small citizen science contribution to understanding and recording these signs better.
Unfortunately, just as I completed this article, the Frogwatch Program discovered that its funding from the ACT Government was not renewed in the 2018–19 budget. Without core funding, the organisation and its annual Frog Census will cease. The enthusiasm of volunteers will help to collect another season’s data for the climate change study but it too is under serious threat unless alternative funding can be sourced.
When our monitoring season finished last year, I asked my daughter whether she wanted to do it again. “Yes,” she replied without hesitation. “What did you like most about it?” I asked. “I don’t know,” she said, “it was just fun.” And so, as Canberra’s heavy frosts set in, we have begun again, treading up towards FMC200, waiting for frog calls to begin.
Saskia Beudel’s full interview with Pep Canadell will be published in December 2018 in the journal Weber.
To the chagrin of the tourist industry, the Great Barrier Reef has become a notorious victim of climate change. But it is not the only Australian ecosystem on the brink of collapse.
Our research, recently published in Nature Climate Change, describes a series of sudden and catastrophic ecosystem shifts that have occurred recently across Australia.
These changes, caused by the combined stress of gradual climate change and extreme weather events, are overwhelming ecosystems’ natural resilience.
Australia is one of the most climatically variable places in the world. It is filled with ecosystems adapted to this variability, whether that means living in scorching heat, bitter cold or a climate that cycles between the two.
Despite land clearing, mining and other activities that transform the natural landscape, Australia retains large tracts of near-pristine natural systems.
Many of these regions are iconic, sustaining tourism and outdoor activities and providing valuable ecological services – particularly fisheries and water resources. Yet even here, the combined stress of gradual climate change and extreme weather events is causing environmental changes. These changes are often abrupt and potentially irreversible.
They include wildlife and plant population collapses, the local extinction of native species, the loss of ancient, highly diverse ecosystems and the creation of previously unseen ecological communities invaded by new plants and animals.
Australia’s average temperature (both air and sea) has increased by about 1°C since the start of the 19th century. We are now experiencing longer, more frequent and more intense heatwaves, more extreme fire weather and longer fire seasons, changes to rainfall seasonality, and droughts that may be historically unusual.
The interval between these events has also shortened, which means even ecosystems adapted to extremes and high natural variability are struggling.
As climate change accelerates, the magnitude and frequency of extreme events is expected to continue increasing.
What is ecosystem collapse?
Gradual climate change can be thought of as an ongoing “press”, on which the “pulse” of extreme events are now superimposed. In combination, “presses” and “pulses” are more likely to push systems to collapse.
We identified ecosystems across Australia that have recently experienced catastrophic changes, including:
kelp forests shifting to seaweed turfs following a single marine heatwave in 2011;
the destruction of Gondwanan refugia by wildfire ignited by lightning storms in 2016;
dieback of floodplain forests along the Murray River following the millennial drought in 2001–2009;
large-scale conversion of alpine forest to shrubland due to repeated fires from 2003–2014;
community-level boom and bust in the arid zone following extreme rainfall in 2011–2012, and
mangrove dieback across a 1,000km stretch of the Gulf of Carpentaria after a weak monsoon in 2015-2016.
Of these six case studies, only the Murray River forest had previously experienced substantial human disturbance. The others have had negligible exposure to stressors, highlighting that undisturbed systems are not necessarily more resilient to climate change.
The case studies provide a range of examples of how presses and pulses can interact to push an ecosystem to a “tipping point”. In some cases, a single extreme event may be sufficient to cause an irreversible regime shift.
In other systems, a single extreme event may only be sufficient to tip the ecosystem over the edge when gradual declines in populations have already occurred. More frequent extreme events can also lead to population collapse if a species does not have enough time to recover between events.
But not all examples can be directly linked to a single weather event, or a series of events. These are most likely caused by multiple interacting climate “presses” and “pulses”. It’s worth remembering that extreme biological responses do not always manifest as an impact on the dominant species. Cascading interactions can trigger ecosystem-wide responses to extreme events.
The cost of intervention
Once an ecosystem goes into steep decline – with key species dying out and crucial interactions no longer possible – there are important consequences.
Apart from their intrinsic worth, these areas can no longer supply fish, forest resources, or carbon storage. It may affect livestock and pasture quality, tourism, and water quality and supply.
Unfortunately, the sheer number of variables – between the species and terrain in each area, and the timing and severity of extreme weather events – makes predicting ecosystem collapses essentially impossible.
Targeted interventions, like the assisted recolonisation of plants and animals, reseeding an area that’s suffered forest loss, and actively protecting vulnerable ecosystems from destructive bushfires, may prevent a system from collapsing, but at considerable financial cost. And as the interval between extreme events shorten, the chance of a successful intervention falls.
Critically, intervention plans may need to be decided upon quickly, without full understanding of the ecological and evolutionary consequences.
How much are we willing to risk failure and any unintended consequences of active intervention? How much do we value “natural” and “pristine” ecosystems that will increasingly depend on protection from threats like invasive plants and more frequent fires?
We suspect the pervasive effects of the press and pulse of climate change means that, increasingly, the risks of doing nothing may outweigh the risks of acting.
The beginning of this century has seen an unprecedented number of widespread, catastrophic biological transformations in response to extreme weather events.
This constellation of unpredictable and sudden biological responses suggests that many seemingly healthy and undisturbed ecosystems are at a tipping point.
Rebecca Harris, Climate Research Fellow, University of Tasmania; David Bowman, Professor, Environmental Change Biology, University of Tasmania, and Linda Beaumont, Senior Lecturer, Macquarie University