Five things we’ve learnt about water in the Pilbara


Home to some of the most stunning Australian landscapes, the Pilbara region and its inhabitants can only survive this extreme environment by understanding the scarce water supply.

Last week the world watched on as NASA announced the discovery of flowing water on Mars. This week we’re analysing water on a patch of red dirt a little closer to home.

The Pilbara – a 500,000 square kilometre stretch of land that’s home to 50,000 people in northern Western Australia. It’s hot, dusty… and full of minerals. The region’s high-grade iron ore deposits, significant deposits of gold, manganese, copper and uranium, not to mention the offshore gas reserves, make it one of the world’s most important resource regions.

It’s also a region that is rich in environmental and cultural values, and has significant areas of grazing land. Whether it’s the vast reserves of iron ore, the spectacular diversity of plants and animals, or some of the oldest living Indigenous cultures in the world, there’s one resource they all depend on — water.

Front-Hamesley Ranges

The Hamersley Range stretches across the Pilbara region and includes some of the world’s oldest rock formations.

That’s why we joined forces with the Government of Western Australia and BHP Billiton to conduct the biggest study into the water resources of the Pilbara, ever – it even has a catchy name: the Pilbara Water Resource Assessment.

It took three years and dozens of researchers, but we now have a body of knowledge that will help guide water planning and management for the Pilbara into the future.

Here are some of the interesting things we’ve learnt:

1. Ten times more water can evaporate in the Pilbara than falls as rain

Because of the blistering extreme heat in the Pilbara, surface water doesn’t last long. The Assessment found that the potential evaporation exceeds annual rainfall by 6 to 14 times, depending on the location within the Pilbara. Despite this, fresh water sources are quite common throughout the region.

2. Groundwater is the most important water source

This is a bit of a no brainer when you consider the first point. Groundwater is currently the main water resource used by towns and industry. This groundwater is not only vital to communities, but it also supports a range of ecosystems, usually near river pools and springs. These ecosystem include species of Acacia found nowhere else, one of the richest assemblages of reptiles in the world, and some of Australia’s iconic mammals – such as the northern quoll and greater bilby.

The greatest variety of ecosystems which depend on groundwater were found in the Hamersley Range.

Ecosystems are supported where groundwater is discharged to river pools and springs

It might be picturesque, but for the ecosystems of the Pilbara the groundwater discharged by these river pools and springs is absolutely vital for survival.

3. We know what it takes to make a stream flow

Between 8 and 30 mm of rain is required for runoff to occur in most Pilbara catchments, which makes the streams and rivers flow. This is important because runoff is the main way the region’s aquifers will be recharged with water. The runoff leaks through streambeds into shallow aquifers just under the surface and from there is able to replenish deeper aquifers, which can store large quantities of water within inland areas.

4. The Pilbara is almost certainly getting hotter

Despite the uncertainty inherent in predicting future climate, there’s one thing that all the Global Climate Models used in this study agree on – the Pilbara is getting hotter. The assessment team used the same modelling tools used by the Intergovernmental Panel on Climate Change to determine what the future climate might look like in the Pilbara. The models project temperatures will be about 1°C warmer by 2030 and 2°C warmer by 2050, compared with 1980s temperatures.

5. It is getting dryer… and wetter

The team assessed the rainfall trends for the area and found that between 1961 and 2012 the east of the Pilbara had become wetter and the west of the area had become drier. They also used the climate models to predict future rainfall for the Pilbara and the models were split on whether the future would be warmer and drier, or warmer and wetter.

Rainfall in the Pilbara results from both tropical weather processes from the north and temperate weather processes from the south. This makes it difficult to predict future rainfall trends for the region because the modelling suggests these processes will respond differently to any increases in greenhouse gases into the future.

On balance, the climate projections carried out by the Assessment team indicate the Pilbara may become slightly drier by 2030 and 2050. But they’re not ruling out the potential for a wetter future either — they modelled a range of wet and dry future scenarios so water managers can be prepared.

If this makes you thirsty for more information about the Pilbara’s water check out the Assessment’s final reports. You can also enjoy a selection of images from this stunning region in the gallery below.

The Pilbara Water Resource Assessment was funded by CSIRO, the Government of Western Australia and BHP Billiton. The project was led by CSIRO and overseen by officers from the Department of Water, BHP Billiton, the Pilbara Development Commission and the Water Corporation.

Media contact:

Chris McKay | +61 7 3833 5728 | +61 455 085 247 |

Reducing emissions alone won’t stop climate change: new research

Replanting forests

Replanting forests is one way to remove carbon dioxide from the atmosphere. This is a site in China. CIFOR/Flickr, CC BY-NC-ND

Richard Matear, CSIRO and Andrew Lenton, CSIRO

Based on current greenhouse gas emissions, the world is on track for 4C warming by 2100 – well beyond the internationally agreed guardrail of 2C. To keep warming below 2C, we need to either reduce our emissions, or take carbon dioxide out of the atmosphere.

Two papers published today investigate our ability to limit global warming and reverse the impacts of climate change. The first, published in Nature Communications, shows that to limit warming below 2C we will have to remove some carbon from the atmosphere, no matter how strongly we reduce emissions.

The second, in Nature Climate Change, shows that even if we can remove enough CO2 to keep warming below 2C, it would not restore the oceans to the state they were in before we began altering the atmosphere.

How we’re tracking

Currently, we’re at 400 parts per million – rising from 280 ppm before the industrial revolution.

To project future climate change the Intergovernmental Panel on Climate Change (IPCC) uses a range of emissions scenarios called Representative Concentration Pathways (RCPs), based on different economic and energy use assumptions.

In the high scenario, RCP8.5, emissions continue to grow from our present rate of 37 billion tonnes of CO2 per year to about 100 billion tonnes of CO2 in 2100, when atmospheric CO2 levels are projected to be 950 ppm. This scenario assumes little mitigation of our carbon emissions.

In the low scenario, RCP2.6, emissions rise slowly till the end of this decade to about 40 billion tonnes CO2 each year and then start to decline. Amongst the IPCC emission scenarios, only the RCP 2.6 appears capable of limiting warming to below 2C. With RCP 2.6 at the end of the century atmospheric concentrations is about 420 ppm, and only 20 ppm above the present value.

Present emissions are tracking close to the highest scenario (RCP8.5). If we want to keep warming below 2C it requires a substantial reduction in the amount of CO2 released into the atmosphere.

What we have to do

We have two options by which to reduce emissions, the first through reducing the use of fossil fuel energy, and the second through Carbon Dioxide Removal (CDR).

CDR refers to technologies that remove CO2, the primary greenhouse gas, from the atmosphere. Examples include Biomass Energy with Carbon Capture and Storage (BECCS), afforestation (planting trees), adding iron to the ocean, and directly capturing CO2 from the air.

For many CDR technologies the boundary between “climate intervention” (or “geoengineering”) and greenhouse gas mitigation is unclear. However, the goal is the same, enhancing the CO2 current taken up and sequestered by the land and ocean.

Can we just remove carbon?

The first study, led by Thomas Gasser, used results from 11 Earth System Models, in conjunction with a simple carbon-cycle models to simulate different emissions reductions scenarios associated with the low emissions pathway, RCP2.6.

They showed that under all emissions reductions scenarios, even slashing emissions to less than 4 billion tonnes CO2 each year, (greater than a 90% cut in current emissions) is insufficient to limit warming to 2C.

This means that some form of CDR will be required to keep warming at less than 2C. The exact level of CDR required depends very much on the emissions reduction achieved, from 2 billion to 10 billion tonnes of CO2 each year in the most optimistic scenario, to between 25-40 billion tonnes CO2 each year in the lowest emission reduction case. This is equivalent to current total global emissions.

The study also suggests that the requirements for CDR may indeed be even higher if unanticipated natural carbon cycle (positive) feedbacks were to occur. We may desire the ability to remove more carbon from the atmosphere to compensate for these.

The other study, led by Sabine Mathesius, explores whether CDR under high CO2 emissions can achieve a similar environmental outcome to a rapid transition to a low carbon energy use (RCP2.6).

It shows that aggressive CDR can only undo the effect of high emissions (RCP8.5) and return the marine environment to either pre-industrial values or the low emission scenario over thousands of years. The ability to undo the damage caused by high emissions reflects timescale of the ocean carbon cycle. While the upper ocean quickly reaches equilibrium with the atmosphere, the deeper ocean takes millennia to restabilise.

Such irreversibility of the system is an important consequence and the study provides valuable information to consider as we tackle rising CO2 levels. Both studies are theoretical but they provide an important perspective on the ability of mankind to engineer the climate system and undo the effects of high CO2 levels in the atmosphere.

No CDR or suite of CDR technologies exists capable of removing the levels of CO2 at the upper range of what maybe required. This means that, while CDR could aid in limiting global temperatures below 2C, in practice this is not even yet possible, and would not be without risks. This continues to be a very active area of research.

While the focus of both studies explore reversing the environmental changes of rising CO2, the climate system is complex and the possibility that mitigation options like CDR could produce unforeseen impacts is high. While reducing carbon emissions is the safest and preferred path for avoiding dangerous climate change and ocean acidification, it is likely that some CDR will be required to achieve this.

The authors will be one hand for an Author Q&A on Tuesday, August 4 – Andrew between 3 and 4pm AEST and Richard between 5 and 6pm AEST. Post your questions in the comments section below.

The Conversation

Richard Matear is Senior Research Scientist, Marine and Atmospheric Research at CSIRO.
Andrew Lenton is Senior Research Scientist, CSIRO Oceans and Atmosphere Flagship at CSIRO.

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

A tale of three mosquitoes: how a warming world could spread disease

Will climate change cause mosquito-borne diseases to spread? Image: Steve Doggett

Will climate change cause mosquito-borne diseases to spread? Image: Steve Doggett

David Yeates, CSIRO

Changing wildlife: this article is part of a series looking at how key species such as bees, insects and fish respond to environmental change, and what this means for the rest of the planet.

As the world warms, animals and plants will shift their ranges to keep pace with their favoured climate. While the changing distributions of species can tell us how climate change is affecting the natural world, it may also have a direct impact on us.

One good example is the disease carried by insects.

Those small, familiar flies called mosquitoes are responsible for much human suffering around the globe because of their ability to transmit diseases.

Mosquitoes transmit a number of viruses, such as Dengue, Ross River Virus, Murray Valley Encephalitis Virus and the local variant of the West Nile Virus known as Kunjin.

Could climate change cause these diseases to spread? While this an extremely important health question, the answer is far from simple.

Complicated life cycle

The life cycle of mosquitoes and its viral parasites is particularly complicated.

Only adult females consume blood, and the immature stages (larvae) live in fresh or brackish water, filtering out small organic particles.

The virus undergoes certain parts of its lifecycle inside particular mosquito organs, but also requires other organs in the vertebrate host to complete its life cycle. And to get into a vertebrate, such as us, it relies on a hungry blood-sucking insect.

These viruses always have other hosts besides humans, which may include native and domestic animals. The pathway that these viruses take to infect humans is often via our domestic animals, which are also bitten by the same mosquitoes that feed on us.

In addition, rates of virus transmission to humans is also affected by the human built environment, and also human behaviour.

Because mosquitoes breed in water, changes in rainfall patterns are likely to change the distribution and abundance of mosquitoes, and therefore could affect disease transmission.

The larvae of Aedes notoscriptus, which carries the Barmah Forest and Ross River viruses. Image: Stephen Doggett

Australian climate is characterised by its variability, however we have experienced a general trend towards increased spring and summer monsoonal rain across northern Australia, and decreased late autumn and winter rainfall in the south.

Flooding rains

Kunjin virus is mainly transmitted by a small mosquito called Culex annulirostris, the common banded mosquito, in Australia. We are lucky because human infection rarely causes disease, even though Kunjin and the common-banded mosquito are widespread in Australia.

Kunjin’s close relative, the US strain of West Nile Virus is much more virulent, causing more human disease. These viruses are well known for their ability to mutate quickly, so they are always keeping medical authorities on their toes.

Higher than average rainfall and flooding in eastern Australia in the second half of 2010 and 2011 provided ideal conditions for breeding common banded mosquitoes, and in 2011 a dangerous strain of Kunjin appeared that caused acute encephalitis (swelling of the brain) in horses. This disease has only been detected in one human, however this mosquito feeds on both humans and horses.

This new virulent strain of Kunjin also appeared in new areas east of the Great Dividing Range, suggesting other unknown changes in transmission.

As temperatures increase, mosquito activity will begin earlier in the season and reach higher levels of abundance sooner, and maintain higher populations longer. These factors will all probably tend to increase the rate of transmission of Kunjin to both humans and animals.

Drying out

While flooding may have helped spread Kunjin, drought may have helped another mosquito-borne virus.

It would be simple to assume that drought would reduce mosquito populations by reducing the larval habitat (water), and thereby reduce the incidence of mosquito-borne disease in Australia.

However, this is not necessarily the case. Another Australian mosquito, Aedes notoscriptus, the striped mosquito, is responsible for transmitting Ross River and Barmah Forest Virus in Australia.

Mosquitoes will breed wherever there is standing water. Image: Suzanne Phillips/Flickr, CC BY-NC

The striped mosquito is unusual in comparison to its cousins because it breeds in small containers of water, such as tree holes in natural environments. The main carrier of Dengue in Australia, Aedes aegypti, shares this habit.

These small container habitats abound in Australia’s urban backyard, with water features, water and food bowls for pets, and various toys providing such breeding places.

With the drought, Australians became much more water wise, and installed various water storage devices in their gardens, ranging from buckets left out in a storm, to professionally installed rain tanks. All these are potential habitat for the striped mosquito to breed.

In this case drought has caused an increase in the abundance of a mosquito virus carrier because of a change in human behaviour.

The return of Dengue?

Dengue fever is transmitted in Australia by the mosquito Aedes aegypti. The mosquito is restricted to Queensland, and Dengue fever transmission is restricted to coastal northern Queensland.

Recent modelling predicts that moderate climate change would extend the Dengue risk zone to Brisbane, exposing much larger human populations to risk.

However, before the 1930s, Dengue fever transmission was known south almost to Sydney, and Aedes aegypti was known throughout mainland Australia except the deserts.

Both the mosquito, and the disease, have retreated to Queensland since then, and we don’t know why. What is clear is that we don’t really understand what controls the distribution of Aedes aegypti or Dengue in Australia, but given the contraction of the disease in historical time, it is unlikely that a warming climate will produce a simple response in the insect or the disease.

Australian insects will be affected by climate change, but simple predictions based on increasing average temperatures and changing rainfall patterns miss the important effects of complex biological interactions.

In addition, we are only just beginning to use models that are sophisticated enough to consider how insects might evolve under changing climate.

Investing in a deeper understanding of these complex biological webs, and their outcomes for human society, will result in great returns. Our predictions of the future state of Australian plants and animals will become more accurate and we will also improve human health and manage our biodiversity more sustainably into the future.The Conversation

David Yeates is Director of the Australian National Insect Collection at CSIRO.

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

Farming carbon can be a win for wildlife, if the price is right

Koalas are one of the threatened species that could benefit from carbon farming. christopher charles/Flickr, CC BY-NC-SA

Koalas are one of the threatened species that could benefit from carbon farming. christopher charles/Flickr, CC BY-NC-SA

Megan Evans, Australian National University; Anna Renwick, The University of Queensland; Josie Carwardine, CSIRO, and Tara Martin, CSIRO

Climate change and the loss of biodiversity are two of the greatest environmental issues of our time. Is it possible to address both of those problems at once?

In Australia, farmers and landholders will this week be able to apply for payments through the Federal government’s A$2.55 billion Emissions Reduction Fund. Bidders can request funding for projects that reduce emissions using agreed methods, which include approaches relevant to the transport, waste and mining sectors, as well as the land sector: for example, by managing or restoring forests.

Forests hold carbon in vegetation and soils and provide important habitat for native wildlife. Restoring forests in areas where they have been cleared in the past could be good for the climate, good for biodiversity, and generate additional income for landholders.

How well the Emissions Reduction Fund can achieve these benefits will depend on three things: the right approach, the right price, and the right location.

Farming carbon

There are a range of approaches available for restoring forests, and they vary in how quickly carbon can be sequestered, cost, and suitability for wildlife.

For example, fast-growing monocultures such as blue gum plantations can sequester carbon very rapidly, but don’t provide ideal habitat for wildlife. Planting a diversity of native trees and shrubs using an approach called environmental plantings is far more wildlife-friendly, but the costs are higher, and carbon is not stored as quickly.

A third possible approach is to assist the natural regeneration of vegetation. This can be done by fencing off cattle or by ceasing on-farm practises such as burning or disturbance with machinery. Assisted natural regeneration is the cheapest of these three possible methods, and is also good for biodiversity: our recent paper found that it could be a great option for restoring forests in agricultural landscapes across Queensland and northern New South Wales.

Brigalow woodlands allowed to regrow for 3-10 years. Image: John Dwyer

Regenerated brigalow woodlands after 50 years. Image: John Dwyer

Location, location, location

Across Australia, there are a number of places where growing carbon could be a more profitable option than the current land use. Some of these places are more important for biodiversity than others.

The mulga lands of western Queensland may be worth more as carbon farms than other uses. Image: Don Butler

If we’re interested in getting some wins for biodiversity while growing carbon forests, we need to think carefully about the possible opportunities and trade-offs, as the best places for sequestering carbon are not always the most beneficial for biodiversity, and vice versa.

In our recent paper, we found that it is possible to identify where growing forests could provide win-wins for both carbon and biodiversity.

For example, the top 25% of priority areas for environmental plantings could sequester 132 million tonnes of CO2 equivalent annually, which is almost a quarter of Australia’s annual emissions (excluding those caused by land-use change).

Relative priority areas for restoring 139 threatened ecosystems to 30% of original extent using environmental plantings, where carbon is stored at $20/tonne. Pink areas are higher priority, green is lower priority

These high-priority areas for environmental plantings could restore some of the most threatened ecosystems in Australia. There are 139 ecosystem types across the country that have lost more than 70% of their original extent. If it were possible to restore these ecosystems up to 30% of their original extent, they will have a better chance of surviving in the long term.

Restoring parts of the landscape with these ecosystems is a high priority for biodiversity – not only are the ecosystems rare, but many of the birds and animals that depend on these ecosystems are those that are most threatened. For example the brigalow woodlands of south east Queensland, of which less than 10% remain, are home to nationally threatened koalas and a host of other wildlife.

The right price

It will generally be more expensive to grow carbon forests that also provide benefits for biodiversity. This is because the places most profitable for land uses such as agriculture are often where the most threatened species and ecosystems are located.

In our analysis, we found that with a price on carbon equivalent to A$5 per tonne, it would not be profitable to restore threatened ecosystems up to 30% of their original extent. This means that without additional funding from another source, there is limited opportunity to achieve wins for biodiversity if the price on carbon is low.

However, a higher price of A$20 per tonne, reflecting Australia’s 2011-2013 carbon price, could allow up to half of the heavily cleared vegetation types to be restored up to 30% without any additional funding for biodiversity itself. At this A$20 price, we also found that it made more economic sense to farm carbon than the existing land use, in over 1.2 million hectares in Queensland.

This week’s Emissions Reduction Fund auction will be a good first test of how the current approach to carbon farming can provide the dual benefit of restoring habitat for native wildlife and addressing climate change. Our analysis shows that Australia’s climate policies could have a very significant impact on biodiversity – if we think carefully about the right approach, price, and location.

The Conversation

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

Australia’s Next Top climate models

Some of Melbourne’s climate analogues for 2090 under a high emission scenario

Some of Melbourne’s climate analogues for 2090 under a high emission scenario

By Chris Gerbing

We all have an interest in whether rain will dampen our day and a curiosity about what the skies hold for next week. We are all impacted when the weather turns extreme, sometimes in devastating ways. And we have a yearning to know what the future might hold for our climate, so that we can plan ahead.

Weather and climate may never be completely predictable, but science has come far enough for us to be breaking new ground when it comes to projecting what Australia’s climate may look like decades – or even hundreds of years – in the future.

And here’s a sneak peak into the future – by the year 2090, Sydney could have the climate of Brisbane, and Melbourne could have the climate of Dubbo.

Climate models help us to understand our present weather and climate, and also allow us to consider plausible future scenarios of how the climate might change. Climate models are built using mathematical representations of the dynamic Earth system. Their fundamentals are based on the laws of physics including conservation of mass, energy and momentum. They create simulations to tell us what happened or what might happen under a range of different scenarios (such as greenhouse gas concentrations).

Check out this animation about climate models.

Along with the Bureau of Meteorology, we’ve used as many as 40 climate models, produced by international global climate modelling groups, to create projections for Australia’s climate, all the way out to the year 2090. The projections consider up to 15 regions of Australia, a small set of plausible future greenhouse gas scenarios and four future time periods.

Climate change projections are presented as a range of possibilities. This occurs because different models produce different projections. Even though they are based on the same physical laws, such as conservation of mass, moisture and energy, each climate model treats regional processes in the oceans and atmosphere slightly differently. It is important to explore the full range of possibilities in any impact assessment.

Even if we significantly reduce our greenhouse gas emissions as under an intermediate scenario, Melbourne’s annual average climate could look more like that of Adelaide’s, and Adelaide’s climate could be more like that of Griffith in New South Wales.

Eastern Australian coastal sites could see a climate shift to those currently typical of locations hundreds of kilometres north along the coast. Sydney’s climate could resemble that of Port Macquarie, and Coffs Harbour’s climate resembling that of the Gold Coast (by 2050; intermediate emissions).

These analogues, and others for more than 400 towns, can be found using a climate analogues tool –  one of 13 tools that can be found on the Climate Change in Australia website.

This research received funding from the Department of Environment under the Regional Natural Resource Management Planning for Climate Change Fund. Additional funding was provided by CSIRO and the Bureau of Meteorology.

We have published a few articles over on The Conversation which takes a deeper look into the details of these climate models and projections.

Here are five questions about tropical cyclones that you need answered

Tropical Cyclone Marcia swirls menacingly off the Queensland coast. Photo Credit: NASA

Tropical Cyclone Marcia swirls menacingly off the Queensland coast. Photo Credit: NASA

By Simon Torok

Tropical cyclones are an ongoing threat during Australia’s cyclone season, which generally lasts from November to April. On average, the Australian region experiences 13 cyclones a year.

But as the coastlines of Queensland and the Northern Territory are threatened on two simultaneous fronts (Marcia and Lam), we’ve asked our climate scientists what we can expect from tropical cyclones in the future, as Australia’s climate continues to change.

1. Has the frequency of tropical cyclones changed?

Some scientific studies suggest no change and others suggest a decrease in numbers since the 1970s in the frequency and intensity of tropical cyclones in the Australian region.

The Bureau of Meteorology’s satellite record is short and there have been changes in the historical methods of analysis. Combined with the high variability in tropical cyclone numbers, this means it is difficult to draw conclusions regarding changes.

However, it is clear that sea surface temperatures off the northern Australian coast have increased, part of a significant warming of the oceans that has been observed in the past 50 years due to increases in greenhouse gases. Warmer oceans tend to increase the amount of moisture that gets transported from the ocean to the atmosphere, and a warmer atmosphere can hold more moisture and so have greater potential for intense rainfall events.

A rare moment of light captured during the Cyclone Tracey salvage mission. Source: CSIRO archives

A rare moment of light captured during the Cyclone Tracy salvage mission. Source: CSIRO archives

2. Will the frequency of tropical cyclones change in future?

The underlying warming trend of oceans around the world, which is linked to human-induced climate change, will tend to increase the risk of extreme rainfall events in the short to medium term. Studies in the Australian region point to a potential long-term decrease in the number of tropical cyclones each year in future, on average.

On the other hand, there is a projected increase in their intensity. In other words, we may have fewer cyclones but the ones we do have will be stronger. So there would be a likely increase in the proportion of tropical cyclones in the more intense categories (category 4 or 5). However, confidence in tropical cyclone projections is low.

3. What are the impacts of tropical cyclones?

Today, coastal flooding is caused by storm tides, which occur when low-pressure weather systems, cyclones, or storm winds elevate sea levels to produce a storm surge, which combines with high or king tides to drive sea water onshore. Although rare, extreme flooding events can lead to large loss of life, as was the case in 1899 when 400 people died as a result of a cyclonic storm surge in Bathurst Bay, Queensland.

4. How will impacts of tropical cyclones change in future?

With an increase in cyclone intensity, there is likely to be an increased risk of coastal flooding, especially in low-lying areas exposed to cyclones and storm surges. For example, the area of Cairns’ risk of flooding, by a 1-in-100-year storm surge, is likely to more than double by the middle of this century.

5. How can we adapt to expected changes?

Almost all of our existing coastal buildings and infrastructure were constructed under planning rules that did not factor in the impacts of climate change. However, governments are now taking account of changes in climate and sea level through their planning policies. Just as the building codes and rules for Darwin changed in the wake of Cyclone Tracy, so they should now be re-assessed for each region and locality in Australia to take account of climate change.

You can track both Tropical Cyclone Marcia and Lam using our Emergency Response Intelligence Capability tool (ERIC).

ERIC - our emergency response tool displaying the paths of Tropical Cyclone Marcia and Lam across our north-eastern coastlines.

ERIC – our emergency response tool displaying the paths of Tropical Cyclone Marcia and Lam across our north-eastern coastlines.

And we also have more information about our latest climate projections here.

Climate projections show Australia is heading for a much warmer future

Beach scene

Future Sydney? Climate projections show Sydney’s climate could end up more like Brisbane’s. Image: Kevin Gibbons/Flickr, CC BY

By Kevin Hennessy, CSIRO and Penny Whetton, CSIRO

Australia is on track for up to 1.7C of warming this century if the world curbs its greenhouse emissions, but under a worst-case scenario could see anything from 2.8C to 5.1C of warming by 2090, according to new climate change projections released by the CSIRO and the Bureau of Meteorology.

The projections are the most comprehensive ever released for Australia. They are similar to those published in 2007, but based on stronger evidence, with more regional detail. These projections have been undertaken primarily to inform the natural resources management sector, although the information will be useful for planning and managing the impacts of climate change in other sectors.

Possible futures

The new report draws on climate model data used by the Intergovernmental Panel on Climate Change (the IPCC). The Fifth IPCC Assessment Report (AR5), released in 2013 and 2014, used a range various greenhouse gas and aerosol scenarios to project future climate change.

Over the past 10 years, carbon dioxide emissions have been tracking the highest IPCC emission scenario (known as RCP8.5). If there is limited international action to reduce emissions, then projections based on the highest scenario may be realised.

However, if emissions are significantly reduced over the coming decades, then intermediate emissions (RCP4.5) might be feasible. Following the low emissions scenario (RCP2.6) would be very challenging given the current trajectory of carbon dioxide emissions.

How does Australia compare?

By late in this century (2090), Australia’s average warming is projected to be 0.6 to 1.7C for a low emission scenario, or 2.8 to 5.1C under a high emission scenario.

The warming under the high scenario is similar to the global average warming of 2.6 to 4.8C under the high emission scenario reported by the IPCC AR5. However, inland areas of Australia will warm faster than coastal areas.

For example, the Rangelands of inland Australia warm by 2.9-5.3C by 2090 under high emissions, while the East Coast, including Sydney and Brisbane, warms by 2.7-4.7C.

Map showing climate projections

This map shows the annual mean temperature for present climate (A), and late 21st century (B). In each panel the 14C, 20C, and 26C contours are shown with solid black lines. In (B) the same contours from the original climate are plotted as dotted lines to provide the clearest depiction of the shifts in climate.

Historical context

The new projections should be viewed in the context of what has already been observed. Australia has become 0.9C warmer since 1910. Rainfall has increased in northern Australia since the 1970s and decreased in south-east and south-west Australia.

More of Australia’s rain has come from heavy falls and there has been more extreme fire weather in southern and eastern Australia since the 1970s. Sea levels have risen by approximately 20 cm since 1900.

In future, Australia’s average temperature will increase and we will experience more heat extremes and fewer cold extremes. Winter and spring rainfall in southern Australia is projected to decline while changes in other regions are uncertain.

For the rest of Australia, natural climate variability will predominate over rainfall trends caused by increasing greenhouse gases until 2030. By 2090, a winter rainfall decrease is expected in eastern Australia, but a winter rainfall increase is expected in Tasmania.

Historical climate data can be used as an analogue for the future. The analogue could be a location that currently has a climate similar to that expected in another region in the future.

For example, for a warming of 1.5-3.0C and a rainfall decrease of 5-15%, Melbourne’s climate becomes similar to that of Clare in South Australia, Sydney becomes more like Brisbane, and Brisbane becomes more like Bundaberg in inland Queensland.

Extreme rainfall events that lead to flooding are likely to become more intense. The number of tropical cyclones is projected to decrease but they may be more intense and possibly reach further south. Southern and eastern Australia is projected to experience harsher fire weather. The time in drought will increase over southern Australia, with a greater frequency of severe droughts.

A projected increase in evaporation rates will contribute to a reduction in soil moisture across Australia. There will be a decrease in snowfall, an increase in snowmelt, and therefore reduced snow cover.

Sea levels will continue to rise throughout the 21st century and beyond. Oceans around Australia will warm and become more acidic.

What will Australia look like?

Freshwater resources are projected to decline in far south-west and far south-east mainland Australia. Rising sea levels and increasing heavy rainfall are projected to increase erosion and inundation, with consequent damage to many low-lying ecosystems, infrastructure and housing.

Increasing heat waves will increase risks to human health. Rainfall changes and rising temperatures will shift agricultural production zones. Many native species will suffer from reduced habitats and some may face local or even global extinction.

The most vulnerable regions/sectors are coral reefs, increased frequency and intensity of flood damage to infrastructure and settlements, and increasing risks to coastal infrastructure and low-lying ecosystems.

While reductions in global greenhouse gas emissions would increase the chance of slowing climate change, adaptation is also required because some warming and associated climate changes are unavoidable.

The Conversation

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


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