By Albert Van Dijk, Luigi Renzullo, Marta Yebra and Shoshana Rapley
2019 was the year Australians confronted the fact that a healthy environment is more than just a pretty waterfall in a national park; a nice extra we can do without. We do not survive without air to breathe, water to drink, soil to grow food and weather we can cope with.
Every year, we collate a vast number of measurements on the state of our environment: weather, oceans, fire, water, soils, vegetation, population pressure and biodiversity. The data is collected in many different ways: by satellites, field stations, surveys and so on.
We process this data into several indicators of environmental health at both national and regional levels.
The report for 2019, released Sunday, makes for grim reading. It reveals the worst environmental conditions in many decades, perhaps centuries, and confirms the devastating damage global warming and mismanagement are wreaking on our natural resources.
Immediate action is needed to put Australia's environment on a course to recovery.
Environment Scores in the Red
From the long list of environmental indicators we report on, we use seven to calculate an Environmental Condition Score (ECS) for each region, as well as nationally.
These seven indicators – high temperatures, river flows, wetlands, soil health, vegetation condition, growth conditions and tree cover – are chosen because they allow a comparison against previous years. In Australia's dry environment, they tend to move up and down together, which gives the score more robustness. See the interactive graphic below to find the score for your region.
Environmental condition scores by local government area, and values for each of the seven indicators. See more data on www.ausenv.online.
Nationally, Australia's environmental condition score fell by 2.3 points in 2019, to a very low 0.8 out of ten. This is the lowest score since at least 2000 – the start of the period for which we have detailed data.
Condition scores declined in every state and territory. The worst conditions were seen in the Northern Territory (0.2 points), New South Wales (0.3 points) and Western Australia (0.4 points), with the latter also recording the greatest decline from the previous year (-5.7 points).
What is most striking is that almost the entire nation suffered terrible environmental conditions in 2019. In each case, the changes can be traced back to dry, hot conditions. Only parts of Queensland escaped the drought.
Comparing local government areas, the worst conditions occurred in Armidale and Gwydir in northern NSW. In contrast, Winton and Townsville in Queensland escaped the overall poor conditions, thanks to the beneficial impact of high rainfall early in the year – although those same events also caused floods killing around 600,000 livestock.
Extreme Drought and Extreme Heat
So what exactly happened in Australia in 2019 to cause such widespread environmental damage? There were several causes.
Across most of Australia, the environment was already reeling from poor conditions in 2018. Also, cool temperatures in the Indian Ocean delayed the onset of the monsoon in northern Australia and reduced the flow of moisture to the rest of the continent, creating hot and dry conditions. Average rainfall was a mere 229 mm across the continent, the lowest in more than 119 years and probably longer than that.
The heat was also extraordinary. The average number of days above 35°C across the country was 36% more than the average for the 19 years prior.
Values for 15 environmental indicators in 2015, expressed as the change from average 2000-2018 conditions. Similar to national economic indicators, they provide a summary but also hide regional variations, complex interactions and long-term context. ANU Centre for Water and Landscape Dynamics
In eastern Australia, arid and hot conditions pushed farmers and ecosystems deeper into drought. In many regions, dryness and declining protection from wind erosion created the worst soil conditions in at least 20 years. Consequences included several dust storms and widespread dieback of forests, especially in NSW.
The severe drought also affected inland water systems, especially the Darling River and its tributaries. Town water supply reservoirs ran out of water, the rivers stopped flowing, and the heat turned the remaining pools into death traps for fish.
Other rivers in northwest Australia, southeast Queensland and northeast NSW also saw their worst flows in 20 years.
Unprecedented Fires
Of course, 2019 will be remembered as the year of unprecedented bushfires. Nationally, the total area burnt was not unusual, not even when the fires of early 2020 are included. But this is only because fire activity was much below average in northern Australia, where ongoing dry conditions left little vegetation to burn.
The extent of forest fires last year was unprecedented, however. As predicted well in advance, the tinder-dry forests in eastern Australia provided the fuel for a dramatic fire season that started in September. Between then and the first month of 2020, vast areas of forest in New South Wales, eastern Victoria, Kangaroo Island and the Australian Capital Territory went up in flames.
The fires destroyed more than 3,000 homes and directly killed 33 people. Indirectly, the most hazardous air quality in living memory created major but poorly known health impacts. The fires also damaged the reliability of drinking water supplies.
The ecological damage was also profound. Fires raged through ecosystems poorly adapted to fire, from rainforests in tropical Queensland to alpine vegetation in Tasmania and the Snowy Mountains of NSW. It remains to be seen whether they can recover. Across NSW, 35% of rainforests were turned to cinders.
About 191 species of animals and plants saw more than one-third of their living area burnt, among them 52 species that were already threatened. Thankfully, the last remaining stands of the prehistoric Wollemi pine and the rare Nightcap Oak were saved.
Even before the fires, 40 plant and animal species were added to the threatened list in 2019, bringing the total to 1890. Following the fires, more species are likely to be added in 2020.
We're Not Doomed Yet
Last year was neither an outlier nor the "new normal" – it will get worse.
Greenhouse gas concentrations continued to increase rapidly in 2019, causing the temperature of the atmosphere and oceans to soar. Australia's population also continued to grow quickly and with it, greenhouse gas emissions and other pollution, and our demand for land to build, mine and farm on.
Whether we want to hear it or not, last year represented another step towards an ever-more dismal future, unless we take serious action.
The current coronavirus pandemic shows that as individuals, and collectively, we can take dramatic action once we acknowledge the urgency of a threat. By comparison, addressing environmental decline will cost less, whereas the long-term costs of not acting will be far greater.
There is much we can do. In the short term, we can help our natural ecosystems recover from the drought and fires. Government agencies and land owners can cull and manage invasive species in fire-affected areas – from weeds, to foxes, cats and feral horses – and stop damaging logging in fire-affected areas.
Individuals can do their bit. We can donate money or time to organizations committed to helping ecosystems recover. Record what you see on bushwalks to help environmental managers monitor and assist ecological recovery.
But the damage of climate change is not limited to natural environments. We must get serious about curbing greenhouse emissions. Humanity has the tools, technology and ingenuity to do it and Australia, one of the countries worst affected by climate change, should lead the world.
Beyond that, individuals can also make a contribution: recycle and reuse rather than buy new, choose low-emission and renewable energy technology and reduce waste – it can save money even now. Let governments and politicians hear your voice. Try to convince friends and family that things need to change.
In the long term, we must find a more balanced relationship with the natural world, understanding that our own survival will depend on it.
The full report and webinar are available here.
Albert Van Dijk is a professor of water and landscape dynamics at the Fenner School of Environment & Society, Australian National University.
Luigi Renzullo is a senior research fellow at Australian National University.
Marta Yebra is a senior lecturer at Australian National University.
Shoshana Rapley is a research assistant at Australian National University.
Disclosure statements: The Australia's Environment report is fully self-funded by ANU. Albert Van Dijk receives or has previously received funding from several government-funded agencies, grant schemes and programs.
Luigi Renzullo receives receives or has previously received funding from several government-funded agencies, grant schemes and programs.
Marta Yebra receives or has previously received funding from several government-funded agencies, grant schemes and programs.
Shoshana Rapley does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond her academic appointment.
Reposted with permission from The Conversation.
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These longer periods of stratification could have "far-reaching implications" for lake ecosystems, the paper says, and can drive toxic algal blooms, fish die-offs and increased methane emissions.
The study, published in Nature Communications, finds that the average seasonal lake stratification period in the northern hemisphere could last almost two weeks longer by the end of the century, even under a low emission scenario. It finds that stratification could last over a month longer if emissions are extremely high.
If stratification periods continue to lengthen, "we can expect catastrophic changes to some lake ecosystems, which may have irreversible impacts on ecological communities," the lead author of the study tells Carbon Brief.
The study also finds that larger lakes will see more notable changes. For example, the North American Great Lakes, which house "irreplaceable biodiversity" and represent some of the world's largest freshwater ecosystems, are already experiencing "rapid changes" in their stratification periods, according to the study.
'Fatal Consequences'
As temperatures rise in the spring, many lakes begin the process of "stratification." Warm air heats the surface of the lake, heating the top layer of water, which separates out from the cooler layers of water beneath.
The stratified layers do not mix easily and the greater the temperature difference between the layers, the less mixing there is. Lakes generally stratify between spring and autumn, when hot weather maintains the temperature gradient between warm surface water and colder water deeper down.
Dr Richard Woolway from the European Space Agency is the lead author of the paper, which finds that climate change is driving stratification to begin earlier and end later. He tells Carbon Brief that the impacts of stratification are "widespread and extensive," and that longer periods of stratification could have "irreversible impacts" on ecosystems.
For example, Dr Dominic Vachon – a postdoctoral fellow from the Climate Impacts Research Centre at Umea University, who was not involved in the study – explains that stratification can create a "physical barrier" that makes it harder for dissolved gases and particles to move between the layers of water.
This can prevent the oxygen from the surface of the water from sinking deeper into the lake and can lead to "deoxygenation" in the depths of the water, where oxygen levels are lower and respiration becomes more difficult.
Oxygen depletion can have "fatal consequences for living organisms," according to Dr Bertram Boehrer, a researcher at the Helmholtz Centre for Environmental Research, who was not involved in the study.
Lead author Woolway tells Carbon Brief that the decrease in oxygen levels at deeper depths traps fish in the warmer surface waters:
"Fish often migrate to deeper waters during the summer to escape warmer conditions at the surface – for example during a lake heatwave. A decrease in oxygen at depth will mean that fish will have no thermal refuge, as they often can't survive when oxygen concentrations are too low."
This can be very harmful for lake life and can even increase "fish die-off events" the study notes.
However, the impacts of stratification are not limited to fish. The study notes that a shift to earlier stratification in spring can also encourage communities of phytoplankton – a type of algae – to grow sooner, and can put them out of sync with the species that rely on them for food. This is called a "trophic mismatch."
Prof Catherine O'Reilly, a professor of geography, geology and the environment at Illinois State University, who was not involved in the study, adds that longer stratified periods could also "increase the likelihood of harmful algae blooms."
The impact of climate change on lakes also extends beyond ecosystems. Low oxygen levels in lakes can enhance the production of methane, which is "produced in and emitted from lakes at globally significant rates," according to the study.
Woolway explains that higher levels of warming could therefore create a positive climate feedback in lakes, where rising temperatures mean larger planet-warming emissions:
"Low oxygen levels at depth also promotes methane production in lake sediments, which can then be released to the surface either via bubbles or by diffusion, resulting in a positive feedback to climate change."
Onset and Breakup
In the study, the authors determine historical changes in lake stratification periods using long-term observational data from some of the "best-monitored lakes in the world" and daily simulations from a collection of lake models.
They also run simulations of future changes in lake stratification period under three different emission scenarios, to determine how the process could change in the future. The study focuses on lakes in the northern hemisphere.
The figure below shows the average change in lake stratification days between 1900 and 2099, compared to the 1970-1999 average. The plot shows historical measurements (black), and the low emission RCP2.6 (blue), mid emissions RCP6.0 (yellow) and extremely high emissions RCP8.5 (red) scenarios.
Change in lake stratification duration compared to the 1970-1999 average, for historical measurements (black), the low emission RCP2.6 (blue) moderate emissions RCP6.0 (yellow) and extremely high emissions RCP8.5 (red). Credit: Woolway et al (2021).
The plot shows that the average lake stratification period has already lengthened. However, the study adds that some lakes are seeing more significant impacts than others.
For example, Blelham Tarn – the most well-monitored lake in the English Lake District – is now stratifying 24 days earlier and maintaining its stratification for an extra 18 days compared to its 1963-1972 averages, the study finds. Woolway tells Carbon Brief that as a result, the lake is already showing signs of oxygen depletion.
Climate change is increasing average stratification duration in lakes, the findings show, by moving the onset of stratification earlier and pushing the stratification "breakup" later. The table below shows projected changes in the onset, breakup and overall length of lake stratification under different emission scenarios, compared to a 1970-1999 baseline.
The table shows that even under the low emission scenario, the lake stratification period is expected to be 13 days longer by the end of the century. However, in the extremely high emissions scenario, it could be 33 days longer.
The table also shows that stratification onset has changed more significantly than stratification breakup. The reasons why are revealed by looking at the drivers of stratification more closely.
Warmer Weather and Weaker Winds
The timing of stratification onset and breakup in lakes is driven by two main factors – temperature and wind speed.
The impact of temperature on lake stratification is based on the fact that warm water is less dense than cool water, Woolway tells Carbon Brief:
"Warming of the water's surface by increasing air temperature causes the density of water to decrease and likewise results in distinct thermal layers within a lake to form – cooler, denser water settles to the bottom of the lake, while warmer, lighter water forms a layer on top."
This means that, as climate change causes temperatures to rise, lakes will begin to stratify earlier and remain stratified for longer. Lakes in higher altitudes are also likely to see greater changes in stratification, Woolway tells Carbon Brief, because "the prolonging of summer is very apparent in high latitude regions."
The figure below shows the expected increase in stratification duration from lakes in the northern hemisphere under the low (left), mid (center), and high (right) emission scenarios. Deeper colors indicate a larger increase in stratification period.
Expected increase in stratification duration in lakes in the northern hemisphere under the low (left), mid (centre) and high (right) emissions scenarios. Credit: Woolway et al (2021).
The figure shows that the expected impact of climate change on stratification duration becomes more pronounced at more northerly high latitudes.
The second factor is wind speed, Woolway explains:
"Wind speed also affects the timing of stratification onset and breakdown, with stronger winds acting to mix the water column, thus acting against the stratifying effect of increasing air temperature."
According to the study, wind speed is expected to decrease slightly as the planet warms. The authors note that the expected changes in near-surface wind speed are "relatively minor" compared to the likely temperature increase, but they add that it may still cause "substantial" changes in stratification.
The study finds that air temperature is the most important factor behind when a lake will begin to stratify. However, when looking at stratification breakup, it finds that wind speed is a more important driver.
Meanwhile, Vachon says that wind speeds also have implications for methane emissions from lakes. He notes that stratification prevents the methane produced on the bottom of the lake from rising and that, when the stratification period ends, methane is allowed to rise to the surface. However, according to Vachon, the speed of stratification breakup will affect how much methane is released into the atmosphere:
"My work has suggested that the amount of accumulated methane in bottom waters that will be finally emitted is related to how quickly the stratification break-up occurs. For example, a slow and progressive stratification break-up will most likely allow water oxygenation and allow the bacteria to oxidise methane into carbon dioxide. However, a stratification break-up that occurs rapidly – for example after storm events with high wind speed – will allow the accumulated methane to be emitted to the atmosphere more efficiently."
Finally, the study finds that large lakes take longer to stratify in spring and typically remain stratified for longer in the autumn – due to their higher volume of water. For example, the authors highlight the North American Great Lakes, which house "irreplaceable biodiversity" and represent some of the world's largest freshwater ecosystems.
These lakes have been stratifying 3.5 days earlier every decade since 1980, the authors find, and their stratification onset can vary by up to 48 days between some extreme years.
O'Reilly tells Carbon Brief that "it's clear that these changes will be moving lakes into uncharted territory" and adds that the paper "provides a framework for thinking about how much lakes will change under future climate scenarios."
Reposted with permission from Carbon Brief.
Currently the U.S. Supreme Court has on its docket a case between Texas, New Mexico and Colorado and another one between Mississippi and Tennessee. The court has already ruled this term on cases pitting Texas against New Mexico and Florida against Georgia.
Climate stresses are raising the stakes. Rising temperatures require farmers to use more water to grow the same amount of crops. Prolonged and severe droughts decrease available supplies. Wildfires are burning hotter and lasting longer. Fires bake the soil, reducing forests' ability to hold water, increasing evaporation from barren land and compromising water supplies.
As a longtime observer of interstate water negotiations, I see a basic problem: In some cases, more water rights exist on paper than as wet water – even before factoring in shortages caused by climate change and other stresses. In my view, states should put at least as much effort into reducing water use as they do into litigation, because there are no guaranteed winners in water lawsuits.
Alabama, pay attention to Supreme Court ruling against Florida in water war #Water #SDG6 https://t.co/wIjdoY6Ccr— Noah J. Sabich (@Noah J. Sabich)1617800452.0
Dry Times in the West
The situation is most urgent in California and the Southwest, which currently face "extreme or exceptional" drought conditions. California's reservoirs are half-empty at the end of the rainy season. The Sierra snowpack sits at 60% of normal. In March 2021, federal and state agencies that oversee California's Central Valley Project and State Water Project – regional water systems that each cover hundreds of miles – issued "remarkably bleak warnings" about cutbacks to farmers' water allocations.
The Colorado River Basin is mired in a drought that began in 2000. Experts disagree as to how long it could last. What's certain is that the "Law of the River" – the body of rules, regulations and laws governing the Colorado River – has allocated more water to the states than the river reliably provides.
The 1922 Colorado River Compact allocated 7.5 million acre-feet (one acre-foot is roughly 325,000 gallons) to California, Nevada and Arizona, and another 7.5 million acre-feet to Utah, Wyoming, Colorado and New Mexico. A treaty with Mexico secured that country 1.5 million acre-feet, for a total of 16.5 million acre-feet. However, estimates based on tree ring analysis have determined that the actual yearly flow of the river over the last 1,200 years is roughly 14.6 million acre-feet.
The inevitable train wreck has not yet happened, for two reasons. First, Lakes Mead and Powell – the two largest reservoirs on the Colorado – can hold a combined 56 million acre-feet, roughly four times the river's annual flow.
But diversions and increased evaporation due to drought are reducing water levels in the reservoirs. As of Dec. 16, 2020, both lakes were less than half full.
Second, the Upper Basin states – Utah, Wyoming, Colorado and New Mexico – have never used their full allotment. Now, however, they want to use more water. Wyoming has several new dams on the drawing board. So does Colorado, which is also planning a new diversion from the headwaters of the Colorado River to Denver and other cities on the Rocky Mountains' east slope.
Drought conditions in the continental U.S. on April 13, 2021. U.S. Drought Monitor, CC BY-ND
Utah Stakes a Claim
The most controversial proposal comes from one of the nation's fastest-growing areas: St. George, Utah, home to approximately 90,000 residents and lots of golf courses. St. George has very high water consumption rates and very low water prices. The city is proposing to augment its water supply with a 140-mile pipeline from Lake Powell, which would carry 86,000 acre-feet per year.
Truth be told, that's not a lot of water, and it would not exceed Utah's unused allocation from the Colorado River. But the six other Colorado River Basin states have protested as though St. George were asking for their firstborn child.
In a joint letter dated Sept. 8, 2020, the other states implored the Interior Department to refrain from issuing a final environmental review of the pipeline until all seven states could "reach consensus regarding legal and operational concerns." The letter explicitly threatened a high "probability of multi-year litigation."
Utah blinked. Having earlier insisted on an expedited pipeline review, the state asked federal officials on Sept. 24, 2020 to delay a decision. But Utah has not given up: In March 2021, Gov. Spencer Cox signed a bill creating a Colorado River Authority of Utah, armed with a $9 million legal defense fund, to protect Utah's share of Colorado River water. One observer predicted "huge, huge litigation."
How huge could it be? In 1930, Arizona sued California in an epic battle that did not end until 2006. Arizona prevailed by finally securing a fixed allocation from the water apportioned to California, Nevada and Arizona.
Litigation or Conservation
Before Utah takes the precipitous step of appealing to the Supreme Court under the court's original jurisdiction over disputes between states, it might explore other solutions. Water conservation and reuse make obvious sense in St. George, where per-person water consumption is among the nation's highest.
St. George could emulate its neighbor, Las Vegas, which has paid residents up to $3 per square foot to rip out lawns and replace them with native desert landscaping. In April 2021 Las Vegas went further, asking the Nevada Legislature to outlaw ornamental grass.
The Southern Nevada Water Authority estimates that the Las Vegas metropolitan area has eight square miles of "nonfunctional turf" – grass that no one ever walks on except the person who cuts it. Removing it would reduce the region's water consumption by 15%.
Water rights litigation is fraught with uncertainty. Just ask Florida, which thought it had a strong case that Georgia's water diversions from the Apalachicola-Chattahoochee-Flint River Basin were harming its oyster fishery downstream.
That case extended over 20 years before the U.S. Supreme Court ended the final chapter in April 2021. The court used a procedural rule that places the burden on plaintiffs to provide "clear and convincing evidence." Florida failed to convince the court, and walked away with nothing.
Robert Glennon is a Regents Professor and Morris K. Udall Professor of Law & Public Policy, University of Arizona.
Disclosure statement: Robert Glennon received funding from the National Science Foundation in the 1990s and 2000s.
Reposted with permission from The Conversation.