Going with the throughflow

Hose spraying water

The backyard experiment any hose-owner can try. Image: Flickr / Scott Akerman

By Simon Torok

Here’s a simple backyard science experiment for you to try, which has global implications.

Grab a garden hose, turn it on, and then put your thumb over the end of it. The flow of water thins, while its power intensifies.

Okay, now multiply that by a few million and you have some idea of the impact of recent La Niña conditions on a major ocean current north of Australia.

The Indonesian Throughflow is a series of ocean currents linking the Pacific and Indian Oceans. It carries water from the Pacific to the Indian Ocean through the passages and straits of the Indonesian Archipelago.

Schematic of the ITF. Values of the flow and the major passages are indicated by red. Water enters the ITF from the western Pacific and exits into the Indian Ocean.

Schematic of the ITF. Values of the flow and the major passages are indicated by red. Water enters the ITF from the western Pacific and exits into the Indian Ocean. Image: Wikipedia.

Researchers – led by Janet Sprintall at Scripps Institution of Oceanography in the United States, and including Susan Wijffels from CSIRO in Hobart – have found that the flow of water in the Indonesian Throughflow has become more shallow and intense since the late 2000s due to La Niña conditions, just as the water flow thinned and intensified while you played with that garden hose.

The paper, The Indonesian seas and their role in the coupled ocean-climate system appears in today’s online publication of the journal Nature Geoscience.

The Indonesian Throughflow is the only place in the world where warm equatorial waters flow from one ocean to another; consequently, the throughflow is an important chokepoint in the flow of heat in the climate system.

The paper suggests that human-caused climate change could make this shallowing and intensification a more dominant feature of the Indonesian Throughflow, even under El Niño conditions.

Changes in how much warm water is carried by the Indonesian Throughflow will affect the sea surface temperature, and in turn the patterns of rainfall in our region.

So you may need to think a bit more about how you use that garden hose.


Explainer: El Niño and La Niña

Australia’s weather is influenced by warm water movements in the Pacific. Image: Flickr / Shayan USA, CC BY

Australia’s weather is influenced by warm water movements in the Pacific. Image: Flickr / Shayan USA, CC BY

By Jaci Brown, CSIRO

We wait in anticipation of droughts and floods when El Niño and La Niña are forecast but what are these climatic events?

The simplest way to understand El Niño and La Niña is through the sloshing around of warm water in the ocean.

The top layer of the tropical Pacific Ocean (about the first 200 metres) is warm, with water temperatures between 20C and 30C. Underneath, the ocean is colder and far more static. Between these two water masses there is a sharp temperature change known as the thermocline.

Winds over the tropical Pacific, known as the trade winds, blow from east to west piling the warm top layer water against the east coast of Australia and Indonesia. Indeed, the sea level near Australia can be one metre higher than at South America.

Warm water and converging winds near Australia contribute to convection, and hence rainfall for eastern Australia.

Graphical description of La Niña

La Niña. Image: US National Weather Service

In a La Niña event, the trade winds strengthen bringing more warm water to Australia and increasing our rainfall totals.

Graphical depiction of El Niño

El Niño. Image: US National Weather Service

In an El Niño the trade winds weaken, so some of the warm water flows back toward the east towards the Americas. The relocating warm water takes some of the rainfall with it which is why on average Australia will have a dry year.

In the Americas El Niño means increased rainfall, but it reduces the abundance of marine life. Typically the water in the eastern Pacific is cool but high in nutrients that flow up from the deep ocean. The warm waters that return with El Niño smother this upwelling.

Have El Niño and La Niña always been around?

El Niño and La Niña are a natural climate cycle. Records of El Niño and La Niña go back millions of years with evidence found in ice cores, deep sea cores, coral and tree rings.

El Niño events were first recognised by Peruvian fisherman in the 19th century who noticed that warm water would sometimes arrive off the coast of South America around Christmas time.

Because of the timing they called this phenomenon El Niño, meaning “boy child”, after Jesus. La Niña, being the opposite, is the “girl child”.

Predicting El Niño and La Niña

Being able to predict an El Niño event is a multi-million, possibly billion dollar question.

A pasture in drought

The drought hit Wagga Wagga, NSW, in 2006. Image: Flickr / John Schilling, CC BY-NC-ND

Reliably predicting an impending drought would allow for primary industries to take drought protective action and Australia to prepare for increased risk of dry, hot conditions and associated bushfires.

Unfortunately each autumn we hit a “predictability barrier” which hinders our ability to predict if an El Niño might occur.

In autumn the Pacific Ocean can sit in a state ready for an El Niño to occur, but there is no guarantee it will kick it off that year, or even the next.

Nearly all El Niños are followed by a La Niña though, so we can have much more confidence in understanding the occurrence of these wet events.

A variety of events

Predictability would be even easier if all El Niños and La Niñas were the same, but of course they are not.

Not only are the events different in the way they manifest in the ocean, but they also differ in the way they affect rainfall over Australia – and it’s not straightforward.

The exceptionally strong El Niños of 1997 and 1982 have now been termed Super El Niños. In these events the trade winds weaken dramatically with the warm surface water heading right back over to South America.

Recently a new type of El Niño has been recognised and is becoming more frequent.

This new type of El Niño is often called an “El Niño Modoki” – Modoki being Japanese for “similar, but different”.

In these events the warm water that is usually piled up near Australia heads eastward but only makes it as far as the central Pacific. El Niño Modoki occurred in 2002, 2004 and 2009.

Weather maps

(a) Australian rainfall in 1998 La Niña (May 1998 to March 1999), (b) the 1997 Super El Niño (April 1997 to March 1998), © the 1982 Super El Niño (April 1982 to February 1983) and (d) the 2002 El Niño Modoki (March 2002 to January 2003). Image: (c) Bureau of Meteorology

Australian rainfall is affected by all its surrounding oceans. El Niño in the Pacific is only one factor.

As a general rule though, the average rainfall in eastern and southern Australia will be lower in an El Niño year and higher in a La Niña. The regions that will experience these changes and the strength are harder to pinpoint.

El Niño and climate change

It is not yet clear how climate change will affect El Niño and La Niña. The events may get stronger, they may get weaker or they may change their behaviour in different ways.

Some research is suggesting that Super El Niños might become more frequent with climate change, while others are hypothesising that the recent increase in El Niño Modoki is due to climate change effects already having an impact.

Because climate change in general may decrease rainfall over southern Australia and increase potential evaporation (due to higher temperatures) then it would be reasonable to expect that the drought induced by El Niño events will be exacerbated by climate change.

Given that we are locked into at least a few degrees of warming over the coming century, it’s hard not to fear more drought and bushfires for Australia.

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


Record rains made Australia a giant green global carbon sink

The swollen Fitzroy River in Queensland, Australia, where heavy rains in early 2011 led to extraordinary regrowth with a global impact. Capt. W. M. & Tatters/Flickr, CC BY-NC

The swollen Fitzroy River in Queensland, Australia, where heavy rains in early 2011 led to extraordinary regrowth with a global impact. Image: Capt. W. M. & Tatters/Flickr, CC BY-NC

By Pep Canadell, Executive Director, Global Carbon Project

Record-breaking rains triggered so much new growth across Australia that the continent turned into a giant green carbon sink to rival tropical rainforests including the Amazon, our new research shows.

Published in the international journal Nature, our study found that vegetation worldwide soaked up 4.1 billion tons of carbon in 2011 – the equivalent of more than 40% of emissions from burning fossil fuels that year.

Unexpectedly, the largest carbon uptake occurred in the semi-arid landscapes of Australia, Southern Africa and South America.

The modelled net carbon uptake of the Australian landscape in December 2010 at the start of the big wet (top), compared with December 2009 (bottom).

The modelled net carbon uptake of the Australian landscape in December 2010 at the start of the big wet (top), compared with December 2009 (bottom).

It set a new record for a land-based carbon sink since high-resolution records began in 1958, in a remarkable example of ecosystems working to stabilise the Earth’s climate.

And that had a global impact. While atmospheric carbon dioxide still rose in 2011, it grew at a much lower rate – nearly 20% lower – than the average growth over the previous decade.

Almost 60% of the higher than normal carbon uptake that year, or 840 million tons, happened in Australia. That was due to a combination of factors, including geography and a run of very dry years, followed by record-breaking rains in 2010 and 2011.

Yet our research raises as many questions as it answers – in particular, about whether the Earth’s natural climate control mechanisms could prove even more volatile than previously thought.

The rain that made the world’s ocean fall

From October 2010 to March 2011, an extraordinary rainfall event occurred over most of Australia, which resulted in three-quarters of Queensland being declared a flood disaster zone – an area as big as France, Germany and Italy combined.

Averaged across Australia, the Bureau of Meteorology recorded rainfall of 703 millimetres for 2010 and 708 mm for 2011. That was well above the long-term average of 453 mm for the period of 1900 to 2009.

Excess rain reached most parts of the continent, in what proved to be the wettest two years combined since national climate records began in 1900.

The 2011 La Niña: So strong, the oceans fell. Boening et. al. (2012), CC BY

The 2011 La Niña: So strong, the oceans fell. Image: Boening et. al. (2012), CC BY

Queensland was the worst affected area, with 35 people killed in floods that broke more than 100 river height records, and damaged 30,000 homes and businesses in cities and towns including Brisbane, Ipswich and Toowoomba. (You can see ABC News images of Brisbane before and after the floods here.)

The big rainfall event was part of a global phenomenon called the El Niño Southern Oscillation (ENSO), which reflects atmospheric pressure changes across the tropical Pacific Ocean, in its La Niña phase. It brought above-average rainfall not only to Australia but also to other parts of the world, particularly in southern Africa and northern South America.

The power of La Niña to evaporate water from the oceans was boosted by the ongoing high sea-surface temperatures that are part of a long-term trend of ocean warming. That trend has been shown to be associated with the release of greenhouse gases from the combustion of fossil fuels and deforestation.

This massive rain event was so significant that sensors on-board the twin satellites GRACE estimated a decrease in ocean water mass of 1.8 trillion tons. That remarkable finding was measured by changes in the Earth’s gravitational field, brought about by the transfer of water from the ocean to the atmosphere and land surface.

The drop in global sea level in 2011, which went against the trend of the previous 18 years. Boening et. al. (2012), CC BY

The drop in global sea level in 2011, which went against the trend of the previous 18 years. Image: Boening et. al. (2012), CC BY

This made the ocean’s sea level fall by 5 millimetres from the beginning of 2010 to mid-2011, going against the average sea-level rise of 3mm a year over the previous 18 years associated with global warming.

Australia played a major role in this sea-level fall, for several reasons. It was partly due to vast amounts of rain that fell over Australia. The continent’s hydrological characteristics also played a role, with large impediments for rainfall to flow quickly back to the ocean, such as the large continental interior basins.

And Australia was a country in need of a big drink. The parched continent was emerging from a multi-year drought, particularly in the south-east region, meaning the land acted as a huge sponge, soaking up the heavy rainfall.

Seeing the Earth change colour from above

As a result of the unusually heavy rains, the Earth’s vegetation “greened” in 2011 in ways not measured over the previous 30 years, particularly in the Southern Hemisphere dryland ecosystems.

This global greening was detected by satellites, which observed increases in canopy foliage extent and vegetation water content, which both imply vegetation growth.

Combined, these measurements indicated that the world’s annual production of new plant matter significantly increased in 2011 when compared to the previous decade.

Regions in the Southern Hemisphere including Australia, southern Africa, and temperate South America contributed 80% of the change, especially their savannas and other semi-arid areas.

New growth springing up around the Murray River, Hume Reservoir and Lake Tyrrell in south-eastern Australia, September 2010. NASA, CC BY-NC-ND

New growth springing up around the Murray River, Hume Reservoir and Lake Tyrrell in south-eastern Australia, September 2010. Image: NASA, CC BY-NC-ND

That winter, June to August 2011, Australia was the greenest that it has ever been seen in the satellite period (since 1982).

The same region in September 2006. This and the image above show how growing conditions compared to average mid-September conditions over 2000 to 2011. See more images here: http://1.usa.gov/RSMka6 NASA, CC BY-NC-ND

The same region in September 2006. This and the image above show how growing conditions compared to average mid-September conditions over 2000 to 2011. See more images here: http://1.usa.gov/RSMka6 Image: NASA, CC BY-NC-ND

Our new study in Nature also shows how fire emissions – normally a big factor in reducing Australia’s capacity to store carbon – were suppressed by about 30%, contributing even further to the continent’s greening.

In addition to the unprecedented vegetation greening of Australia during 2010 and 2011, we also observe a greening trend over the continent since 1980s, particularly during the months of the Australian autumn (March, April, and May).

That has happened for a number of reasons, including increased continental rainfall over the past few decades; plants growing in an atmosphere with increasing carbon dioxide using water more efficiently; and changes in land management such as fire suppression, expansion of invasive species, and changes in livestock grazing that have led to more woodland.

The upsides of going green

Despite recurrent drought conditions in some regions, there is a current greening trend over Australia.

Overall, satellites show Australian landscapes are greener now than they have been over the past 30 years.

A greener Australia has a number of environmental and other benefits, including better protection for soils, increased soil-water holding capacity and soil fertility, and more plant feed to sustain larger animal populations.

Green growth flourishing in central Australia, 2011. Eva van Gorsel, CC BY-NC-ND

Green growth flourishing in central Australia, 2011. Image: Eva van Gorsel, CC BY-NC-ND

However, more vegetation can lead to less water being available to replenish water tables and feed rivers, even though Australia loses more than 50% of all the rainfall to the atmosphere as soil evaporation, without contributing to vegetation growth.

This is in sharp contrast to temperate and tropical ecosystems, where a large part of the water is returned to the atmosphere via vegetation.

Fire, drought and rapid carbon release

However, we now need to consider whether this growing accumulation of carbon in semi-arid regions of the Southern Hemisphere could become a future climate liability through fire and drought.

Land and ocean carbon sinks absorb around half of the world’s emissions from burning fossil fuels each year, which helps to slow the rise of atmospheric carbon dioxide concentrations from human activities.

The Intergovernmental Panel on Climate Change’s Fifth Assessment Report found that we are likely to see an increase in climate variability that includes drier, more fire-prone conditions across large parts of the Southern Hemisphere’s semi-arid regions, including Australia.

That’s a vital trend to consider, because it could lead to a more vulnerable global carbon reservoir.

While we might see more carbon stored in new vegetation growth and soil when extra water is available in semi-arid regions, as happened in 2010-2011, the risk is that more fires and droughts would end up rapidly releasing that carbon back to the atmosphere.

Looking ahead

It is likely that the large carbon uptake during 2011 was short-lived, as suggested by a rapid decline of the sink strength in 2012. Future research will be able to confirm if this was the case.

Arid and semi-arid regions currently occupy 40% of the world’s land area. More work is urgently needed to research the best ways to manage these areas, and whether we can increase their soil and vegetation carbon stores as part of our climate mitigation efforts.

While tropical forests like the Amazon remain vitally important as major carbon sinks, this new study and others indicate that semi-arid regions like Australia will also play a growing role in the Earth’s carbon cycle.

Increasingly, semi-arid regions are driving variability in how much carbon dioxide remains in the Earth’s atmosphere each year. And that has major implications for the long-term, including whether future climate change will slow down or accelerate further.

Pep Canadell receives funding from CSIRO and the Department of the Environment. This article is based on a new paper that he was a co-author of: Poulter, B, D Frank, P Ciais, R Myneni, N Andela, J Bi, G Broquet, JG Canadell, F Chevallier, YY Liu, SW Running, S Sitch and GR van der Werf. 2014. The contribution of semi-arid ecosystems to interannual global carbon cycle variability, Nature. Canadell’s contribution was supported by the Australian Climate Change Science Program.

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


The ozone hole saga takes a new twist

The ’70s were all about disco, big hair, gold chains and flares… you can smell the hairspray just thinking about it.

Lady spraying her hair with hairspray

You can’t sport a hairstyle like this without hairspray. Image: Indiewire

But while the hairstyles were getting bigger and badder, scientists were busy making a discovery that would put them on a collision course with this emerging fashion.

The atmosphere’s ozone layer was being depleted – and CFCs (chlorofluorocarbons) were responsible. CFCs were one of the main chemicals in hairspray (as well as every other aerosol product) and were used in refrigerators and air conditioners.

When sunlight hits CFC molecules in the upper atmosphere, they break apart, producing a chlorine atom that in turn reacts with ozone molecules and breaks them apart – see this explanation from the Bureau of Meteorology. The ozone layer provides us Earthlings protection from the Sun’s harmful UV rays.

This discovery led to a landmark international agreement known as the Montreal Protocol of 1987, which saw most of the world’s countries sign on to phase out the use of CFCs. This has largely succeeded to date, with CFCs having been almost completely replaced by a related group of chemicals, hydrofluorocarbons (HFCs), which don’t deplete ozone (although they do have their own set of problems).

Or so we thought.

In research published in the journal Nature Geoscience this week, scientists revealed that they have detected four new ozone-depleting gases in our atmosphere. More than 74,000 tonnes of three new CFCs and one new hydrochlorofluorocarbon (HCFC) – an intermediate form of CFC – have been released into the atmosphere.

While this is a small amount when compared to the peak emissions of other CFCs in the ’80s, these emissions are contrary to what the Montreal Protocol set out to achieve – and so raise questions about where they are coming from.

The team, including our own Dr Paul Fraser, made the discovery by comparing today’s air samples with air trapped in polar firn (compacted snow), providing a natural archive of the atmosphere. They also looked at air samples collected between 1978 and 2012 at our Cape Grim air pollution station in northwest Tasmania.

The source of these new gases remains a mystery.

“We know they are coming from the northern hemisphere, but that is as good as we know at this stage,” Dr Fraser told ABC Science.

“It is good that we have found them quite early and that they haven’t accumulated to a significant degree in terms of ozone-depletion. Now we are hoping to find out where they are coming from so their sources can be switched off.”

Man standing in front of air canisters

Dr Paul Fraser with air samples collected at Cape Grim, Tasmania.


Masking and unmasking of global warming by aerosols

By Leon Rotstayn, Senior Principal Research Scientist, Marine and Atmospheric Research

Climate scientists have established a convincing case for the link between increasing concentrations of greenhouse gases and observed warming of the Earth since the 19th century. The Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) stated, “Human influence on the climate system is clear.

“This is evident from the increasing greenhouse gas concentrations in the atmosphere, positive radiative forcing, observed warming, and understanding of the climate system.” It also concludes that “it is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century.”

Aside from carbon dioxide, another human influence on climate comes from aerosols, which exert a cooling effect. Aerosols (that is, atmospheric particles, not propellants used in spray cans) have masked some of the warming that is caused by increasing greenhouse gases.

Without the masking effect of aerosols, global temperatures would have increased more than they have since the 19th century.

I recently led a study that examined the effects of declining aerosols in 21st century climate projections. We found that global warming is likely to accelerate in the next few decades, if the cooling influence of human-generated aerosols declines as predicted.

The role pollution aerosols play in climate change is incredibly complicated. Image: CzechR/Flickr

The role pollution aerosols play in climate change is incredibly complicated. Image: CzechR/Flickr

What are aerosols?

Aerosols are atmospheric particles, which have an overall cooling influence on climate by reflecting sunlight back into space. They also have an indirect effect by making clouds brighter; this further increases the reflection of sunlight back into space. Sources of human-generated aerosols include the use of fossil fuels and burning of vegetation.

Although human sources of aerosols are broadly similar to those of carbon dioxide, there is an important difference.

Emissions of carbon dioxide are intrinsically linked to the energy content of the fuel, so increasing energy use leads to increasing emissions of carbon dioxide. But aerosols are produced as a by-product of the combustion process, and in many cases there are technologies that can reduce emissions of aerosols (or gases that subsequently form aerosols in the atmosphere).

Because aerosols have harmful effects on human health and the environment, such technologies have been deployed in the industrialised world for some time. As long ago as the mid-1970s, emissions of sulfur dioxide from coal-fired power stations started to decline in Europe and North America, due to controls that were introduced to combat acid rain, which was destroying forests. These controls also had the effect of reducing sulfate, an aerosol that exerts cooling effects on climate.

More recently, authorities in China recognised the problems caused by aerosol pollution, and began to introduce emission controls, similar to those first seen in the industrialised world in the 1970s. Observations in China show that aerosol pollution peaked in 2006, and has started to decrease since then, despite continuing rapid economic growth. However, high levels of aerosol pollution are still causing serious concerns about health effects in China, suggesting that there is a strong need to further reduce emissions.

In many other developing countries, aerosol emissions are still increasing.

Over the last several years, climate modellers from many research centres carried out new climate projections, which provided input to the IPCC Fifth Assessment Report. These climate projections are driven by a range of scenarios (or “pathways”), which have different assumptions about changing levels of greenhouse gases.

A common feature of all the pathways is that aerosol emissions decline sharply during the 21st century. The projected decline is based on the assumption that once wealth per capita reaches a certain level in each country, there will be an increased focus on cleaner, healthier air.

In other words, it is assumed that during the 21st century the developing world will follow a path similar to the industrialised world, where aerosol emissions have declined in recent decades.

What happens to climate if aerosols decline?

Whereas increasing aerosols have masked global warming in the past, projected declines in aerosol emissions would unmask the warming effects of increasing greenhouse gases.

We are currently going through a transition. Until recently, aerosols have been acting like a “handbrake” on global warming. Over the next few decades, the decline of aerosols is expected to accelerate global warming, adding to the effects of increasing greenhouse gases.

Results from CSIRO climate modelling suggest that the extra warming effect from a decline in aerosols could be about 1 degree by the end of the century. But the size of this effect is very uncertain, so we compared the results from the CSIRO model with those from a range of international models.

We found that models with a stronger aerosol cooling effect in the 20th century tend to simulate greater warming in the 21st century. In other words, climate models with a stronger aerosol masking effect also have a stronger unmasking effect as aerosols decline.

Understanding aerosol effects is one of the biggest challenges for climate scientists. Aerosol processes are highly complex, and the magnitude of aerosol cooling effects in today’s climate is uncertain.

Every aerosol plume contains a mind-boggling soup of different chemical species; some of these (most notably black carbon) actually exert warming effects on climate, partly offsetting the cooling effects of other species such as sulfate. It is also unclear whether aerosols will really decline as rapidly as assumed in the projections.

Aerosols present an intriguing policy challenge. Concerns about toxic effects of aerosols on health and the environment provide strong reasons to reduce their emissions. But a uniform reduction in aerosol emissions is expected to accelerate global warming.

Based on this research, scientists have suggested that selectively reducing black carbon emissions is a possible option for mitigating global warming that will also have important health benefits.

Leon Rotstayn receives funding from the Australian Government Department of the Environment through the Australian Climate Change Science Programme.

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

More climate news on our Climate Response blog.


Fire and climate change: fire risk needs to be managed

By Kevin Hennessy, Principal Research Scientist, Marine & Atmospheric Research

Recent fires in New South Wales highlight our current vulnerability, remind us about potential future risks and prompt us to think more strategically about risk management. Some key questions have come to the fore, such as:

Is climate change to blame for the NSW fires?

Bushfires are influenced by many factors including: warmer and drier conditions in preceding months, days with extreme heat, strong winds and low humidity, urban development patterns, fuel loads and management.

We’ve just experienced Australia’s warmest 12-month period on record, NSW had its warmest January-September on record, and eastern NSW has been very dry.

Together with accumulated fuel loads over the past few years, this provides conditions that increase fire risk. Other parts of Australia need to prepare for an active fire season.

While it’s almost impossible to attribute an individual extreme weather event to climate change, the risk of fire has increased in south-east Australia due to a warming and drying trend that is partly due to increases in greenhouse gases.

A farm under a cloud of smoke from a bushfire.

We should be talking about future bushfires. Image: AAP Image/Dan Himbrechts

What is fire risk?

Fire is a natural part of the Australian landscape. Fire weather risk can be quantified using the Forest Fire Danger Index (FFDI).

Annual cumulative FFDI, which integrates daily fire weather across the year, increased significantly) at 16 of 38 Australian sites from 1973-2010. The number of significant increases is greatest in the southeast, while the largest trends occurred inland rather than near the coast. The largest increases in seasonal FFDI occurred during spring and autumn, while summer had the fewest significant trends.

This indicates a lengthened fire season.

Fire risk is different to fire weather risk, as fire risk is affected by other factors, such as vegetation and human behaviour, in addition to the weather.

What can we expect in the future?

Climate change over the coming decades is likely to significantly alter fire patterns, their impact and their management in Australia.

An increase in fire-weather risk is likely with warmer and drier conditions in southern and eastern Australia.

The rate of increase depends on whether global greenhouse gases follow a low or high emission scenario. Carbon dioxide emissions have been tracking the high scenario over the past decade.

The number of “extreme” fire danger days in south-east Australia generally increases 5-25% by 2020 for the low scenarios and 15-65% for the high scenarios. By 2050, the increases are generally 10-50% for the low scenarios and 100-300% for the high scenarios. This means more total fire ban days.

Fire danger periods are likely to be more prolonged, so the fire season will lengthen.

What should we do now?

Without adaptation, there will be increased losses associated with the projected increase in fire weather events.

Adaptation in the short-term can lead to greater preparedness, including many well established actions such as fire action plans, vegetation management and evacuations; while adaptation in the long-term can reduce the fire risk experienced by society, through actions such as appropriate building standards and planning regulations in fire-prone areas.

Kevin Hennessy receives funding from the Commonwealth Department of Environment.

The Conversation

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


She’s a social researcher looking to save the planet – and save us money!

NinaInYosemite_web

Nina’s work has taken her to some breathtaking sites, including Yosemite Falls in California.

Nina Hall is fired up. She wants to contribute to a future that we all want to experience – one that sees good health for ourselves and our environment.

Nina is the leader of EnergySavers, a project aimed at empowering low income individuals to move to energy efficient behaviours and reduce their greenhouse gas emissions. This means saving money on power bills, and getting the best value out of the energy that is used.

“The project has been particularly popular among refugee participants who value the interactive introduction to using energy in Australia, and low-income seniors who appreciate the opportunity to better manage their pensions,” says Nina.

Last year, Nina was lucky enough to present the emerging results of the EnergySavers program at the Behavior, Energy and Climate Change conference in California. She even squeezed in a quick trip to Yosemite National Park before coming home.

Nina began her career investigating environmental issues, but as the science on climate change crystallised she moved her focus to climate change and energy consumption.

“I see myself as a change agent, working directly from published work and through a very respected and independent organisation.”

With such a busy role, you’d think she would have little time to relax. But that’s certainly not the case. Nina is a regular bike rider, bushwalker and swimmer – and still manages to find time for her hubby and two kids.

For more information on careers at CSIRO, follow us on LinkedIn.


Climate Crab takes us on a Pacific climate journey

By Jill Rischbieth

Communicating climate science in accessible and meaningful ways is always a challenge. A comical and highly resilient climate crab is now taking on this challenge across the Pacific.

We have teamed up with the Bureau of Meteorology and humanitarian experts from the Red Cross to produce ‘The Pacific Adventures of the Climate Crab’. This animation follows the escapades of a comical and highly resilient crab and aims to help Pacific Island communities better understand El Niño and La Niña and how to prepare for these events.

For people living in small Pacific island countries El Niño and La Niña can have very serious impacts. For example, the 2010/2011 La Niña event resulted in severe droughts in Tuvalu and floods in Fiji. The result can be threats to water quality, food security, infrastructure (like houses and roads), livelihoods and health.

But the good news if people are prepared the impacts can be somewhat mitigated. Weather offices can provide warnings and forecasts to help Pacific Islanders anticipate and prepare for changing risks.

The animation comes with a ‘tool kit’ to help link the information presented in the animation to decision-making and action on the ground.

The films and accompanying resources will be useful those working in fields that address climate risk such as climate change adaptation, disaster risk management, health, education, food security, community planning, environmental protection, agriculture and natural resource management.

The series continues in July with a reggae parrot, the next climate communicator to join the climate crab. For more information, visit http://www.pacificclimatechangescience.org/climatecrab


Designing a future Earth

By Chris Johnson

Today, the International Council for Science (ICSU) and the International Social Science Council (ISSC) named Dr Mark Stafford Smith, the Science Director of our Climate Adaptation Flagship, as their inaugural Chair of the scientific committee of Future Earth.

What might the future of the Earth look like?

What does the future hold for our Earth?

Future Earth is a new 10-year international research initiative that will develop the knowledge for responding effectively to the risks and opportunities of global environmental change and for supporting transformation towards global sustainability in the coming decades. It will mobilize thousands of scientists while strengthening partnerships with policy-makers and other stakeholders to provide sustainability options and solutions in the wake of Rio+20.

The scientific committee is made up of 18 members from around the globe. It includes a broad range of disciplines and expertise needed to address global environmental change in all its dimensions, including natural and social sciences, humanities and engineering.

“Future Earth is going to change the way we do science globally. It represents a unique opportunity to provide the research needed to address the biggest challenges of our time on global sustainability, and to do so in partnership with decision-makers,” says Dr Stafford Smith.

Here he is discussing Future Earth in more detail.

Research by Future Earth will address fundamental questions, such as:

  • What risks are humanity facing?
  • Can we adapt to a warmer world?
  • How does global environmental change affect poverty and development?
  • How can the world eradicate poverty while achieving global sustainability?

Learn more about the vision behind Future Earth below.


Surf’s up… and down. Wave heights to change as atmosphere warms

Climate scientists studying the impact of changing wave behaviour on the world’s coastlines are reporting a likely decrease in average wave heights across 25 per cent of the global ocean.

In some of the first climate simulations of modelled wave conditions they also found a likely increase in wave height across seven per cent of the global ocean, predominantly in the Southern Ocean.

gopro_surfer

A lone surfer. Image: Flickr/stevenworster

Lead author, Dr Mark Hemer, said that 20 per cent of the world’s coastlines are sandy beaches which are prone to natural or man-made changes. It is estimated that 10 per cent of these sandy coasts are becoming wider as they build seawards, 70 per cent are eroding and the remaining 20 per cent are stable. Around 50 per cent of Australia’s coast is sand.

“Waves are dominant drivers of coastal change in these sandy environments, and variability and change in the characteristics of surface ocean waves (sea and swell) can far exceed the influences of sea-level rise in such environments.

“If we wish to understand how our coasts might respond to future changes in climate then we need to try and understand how waves might respond to the projected changes in global atmospheric circulation seen as shifts in storm frequency, storm intensity and storm tracks,” Dr Hemer stated.

Dr Hemer explained that coastal impacts of climate change studies have predominantly focused on the influence of sea-level rise and, until now, not focussed on how changing wave conditions will impact the coastal zone in a changing climate.

He said sea-level rise is likely to have considerable influence along much of the world’s coastlines. However, with such poor understanding of how changes in waves and other coastal processes will also influence shoreline position, it is difficult to attribute a level of future risk to the coast under a warmer climate.

Coastal cliffs in Sydney's Royal National Park. Image: Flickr/AndrewBeeston

Coastal cliffs in Sydney’s Royal National Park. Image: Flickr/AndrewBeeston

The study compared results from five research groups from Australia, the United States, Japan, Europe and Canada. Each group used different modelling approaches to develop future wave-climate scenarios.

“While we find agreement in projected change in some parts of the world’s oceans, considerable uncertainty remains. We’re continuing to quantify the dominant sources of variation with the latest generation of climate models which will be used in the up-coming Intergovernmental Panel on Climate Change reports,” Dr Hemer said.

He said climate is one of several mostly human-driven factors influencing coastline change. These findings are derived from a study which seeks to understand potential impacts on coasts from climate change driven wind-wave conditions. The study will be published in the print edition of the journal Nature Climate Change on 25 April.

Media: Craig Macaulay  P: 03 6232 5219  M: 0419 966 465  Email: Craig.Macaulay@csiro.au


Breakfast in 2050: feeding a changing world

A farmer in Nicaragua. Image: N. Palmer (CIAT)

How will we feed the world in 2050? Feeding a growing population is a big challenge, but feeding them in the face of a changing climate, volatile markets and limits on resources means we need to work hard to succeed. According to projections, the maximum amount of food we can produce declines steeply under growing climate pressures, yet we will need more food to make up for global crop losses.

In response to the challenge, CGIAR, a global agricultural research alliance, pulled together the Commission on Sustainable Agriculture and Climate Change and Megan Clark, our Chief, represented Australia. The commission released a report last year on Achieving Food Security in the Face of Climate Change. The report reviewed scientific evidence and produced a set of actions to transform the food system. These recommendations include transforming current patterns of food production, distribution and consumption, and also investment and innovation to empower the world’s most vulnerable populations. For us consumers, actions include eliminating food waste and having access to better sustainability and nutrition information from improved labelling.

This animation goes into more detail on our ‘safe operating space’ in relation to food and climate change.

Today is the one year anniversary of the CGIAR report. Read more about the idea to finished product and their ongoing research on their blog. More on our work tackling food security challenges on our website.


When every penny counts

By Kirsten Lea

Man checking the electricity meter

For the average Aussie, electricity bills represent about 2.3 per cent of their household budget. However, for many of us on an income below the average, it is a huge expense when the bill lands in the mail box each quarter.

Not only do the bills hurt our back pocket, the electricity we use to heat and cool our homes contributes to around 21 per cent of Australia’s greenhouse gas emissions, which is contributing to climate change.

There are things you can do to reduce your bills (and stop climate change) right now. Check out our D-I-Y energy saving tips room by room and start saving on your energy bills!

We are also directly lending a helping hand to older, low income Queenslanders with our EnergySavers program. Thanks to funding from the Australian Government, we are working with Brisbane City Council to help 1000 volunteers make small, but significant, changes to take control of their electricity bills.

The way it works is simple; we bring people together in small groups in a local venue, such as a library or school. The group works through our energy fact sheets, filled with tips and advice, they watch a video and chat over a cup of tea. It’s a friendly, useful way for people to understand what will make a difference to their electricity bills. And it works. We have had great results with similar programs.

Just a handful of changes can save enough electricity to cover the cost of bread and milk for the week.  That’s a big saving when every penny counts.

Find out more about EnergySavers at www.csiro.au/energysavers or call 1300 119 003.


Ocean science robot revolution hits symbolic millionth milestone

An innovative global observing system based on drifting sensors cycling from the surface to the ocean mid-depths is being celebrated by scientists today after reaching a major milestone – one million incredibly valuable ocean observations.

From 10 drifting robotic sensors deployed by Australia in the Indian Ocean in late 1999, the international research program has been quietly building up a global array which is now enabling new insights into the ocean’s central influence on global climate and marine ecosystems.

Global locations for Argo robotic sensors – 4 December 2012.

Global locations for Argo robotic sensors – 4 December 2012.

The initial objective was to maintain a network of 3000 sensors, in ice-free open ocean areas, providing both real-time data and higher quality delayed mode data and analyses to underpin a new generation of ocean and climate services. The program is called Argo.

“We’re still about 50 years behind the space community and its mission to reach the moon,” says Argo co-Chair and CSIRO Wealth from Oceans Flagship scientist, Dr Susan Wijffels.

“The world’s deep ocean environment is as hostile as that in space, but because it holds so many clues to our climate future exploring it with the Argo observing network is a real turning point for science.

“In its short life the Argo data set has become an essential mainstay of climate and ocean researchers complementing information from earth observing satellites and uniquely providing subsurface information giving new insights into changes in the earth’s hydrological warming rates and opening the possibility of longer term climate forecasting,” Dr Wijffels said.

Although the one millionth profile of the upper ocean, measured from the surface to a depth of two kilometres, was achieved in early November, oceanographers around the world are today celebrating this critical benchmark in ocean monitoring which delivers data to a scientist’s desk within 24 hours of sampling.

Celebrations included a series of high-level international presentations by senior scientists involving Dr Wijffels, her Argo co-Chair Prof Dean Roemmich from Scripps Institution of Oceanography, oceanographer Dr Josh Willis from the NASA Jet Propulsion Laboratory, and Dr Jim Cummings from the US Naval Research Laboratory.

The Argo array has risen to now number more than 3500 sensors, the largest there has ever been. The average lifetime of the floats has improved in the past decade greatly increasing the efficiency of the operation.

Presently 28 countries contribute to the annual A$25M cost of operating the program. The US is the largest provider of sensors to the network, with Australia, led by CSIRO with the Integrated Marine Observing System and the Bureau of Meteorology, maintaining more than 300 profilers for deployment mainly in the Indian and Southern Oceans, and Tasman Sea.

The 1.5 metre tall robotic sensors cycle vertically every 10 days, sampling temperature and salinity. At the surface, the sensors despatches its data via satellite to national centres across the globe, where analysts then check it, package it and send it to synchronous assembly centres in France and the US.  The sensor’s ascent and descent is regulated by a hydraulic pump, powered with lithium batteries. Their life expectancy is between 4-9 years, averaging more than 200 profiles per sensor as they drift with the currents and eddies.

Data are collected at the impressive rate of one profile approximately every four minutes, (360 profiles per day or 11000 per month) and on 4 November 2012 Argo passed the symbolic milestone of collecting its one millionth profile. To put this achievement in context, since the start of deep sea oceanography in the late 19th century, ships have collected just over half a million temperature and salinity profiles to a depth of 1km and only 200000 to 2km.  At the present rate of data collection Argo will take only eight years to collect its next million profiles.

Dr Wijffels said almost 1200 scientific papers based on or incorporating Argo data have been generated since the start of the program. Prominent findings include:

  • Analysis of ocean salinity patterns that suggests a substantial (16 to 24%) intensification of the global water cycle will occur in a future 2° to 3° warmer world.
  • A more detailed view of the world’s largest ocean current, the Antarctic Circumpolar Current.
  • An insight into changing bodies of water in the Southern Ocean and the way in which carbon dioxide is removed from the atmosphere.
  • Isolating the effect of ocean warming and thermal expansion on the global energy and sea level budget.

Dr Wijffels said Argo data is now also being widely used in operational services for the community, including weather and climate prediction and ocean forecasting for environmental emergency response, shipping, defence, and safety at sea.

Media: Craig Macaulay Ph: +61 3 6232 5219 Mb: 04199 966 465 E: Craig.Macaulay@csiro.au


Our changing beaches – scientists look for a break in the surf zone

A small team of oceanographers from CSIRO’s Wealth from Oceans Flagship is using a suite of sensors, radar and video cameras, to monitor beach change at Secret Harbour.

The project is part of Australia’s ocean forecasting system, BLUElink, a joint initiative of CSIRO, the Bureau of Meteorology and the Royal Australian Navy, that aims to provide forecasts of ocean currents and eddies, and surface and subsurface ocean properties.

“Ultimately, we are trying to build a capability to forecast changes in surf zone sand bars and gutters as sea, wind and wave conditions change,” says CSIRO’s Dr Graham Symonds.

A suite of sensors are monitoring coastal change at Secret Harbour, near Perth.

A suite of sensors are monitoring coastal change at Secret Harbour, near Perth.

Dr Symonds said Australia’s beaches and shorelines are continually changing with varying wave conditions and sea level.

He said regular beach goers would be familiar with changes in beach shape and shoreline position, for example erosion following storms, or rocky sections exposed during winter and covered with sand during summer. Long term residents may be aware of progressive changes in their local beach over periods of many years.

“In the face of changing sea level, the effects of potential inundation and coastal erosion will continue to be a focus of coastal councils and communities for the foreseeable future.

“Our intention is to harness the data we are acquiring here at Secret Harbour and construct a computer model capable of predicting beach shape and shoreline position under the full range of wave conditions.”

“There’s an immediate application for this research by the Royal Australian Navy with amphibious landings, however it can also be applied to improve beach safety, monitoring coastal erosion and understanding of how beaches might respond to climate change,” said Dr Symonds.

Secret Harbour beach was chosen because it is a relatively straight beach that is typical of some of the Perth metropolitan beaches. In an experiment running since May 2011, the CSIRO science team has constructed a beach tower, installed a radar system, in-water current meters and pressure sensors, and a video camera system, focussing on an area of beach about 1 km long and extending offshore about 500m.

“Waves break over shallow sandbars so video and radar observations of breaking waves provide a measure of the underlying bathymetry. Gaps in the surf zone are associated with deeper water where the waves don’t break and often indicate the location of rip currents.”

Dr Symonds said the laptop-based ocean modelling system for the surf-zone will provide wave and current forecasts several times a day for use by the Royal Australian Navy, and will also be relevant for rescue agencies, environmental protection and recreational marine activities such as fishing and surfing.

The project will help develop a core capacity in wave and near-shore dynamics comparable with that available in ocean and atmosphere dynamics in Australia.

MEDIA: Craig Macaulay. Ph: +61 3 6232 5219. Mb: 0419 996 6465. E: Craig.Macaulay@csiro.au


The widening gap between present emissions and the two-degree target

Carbon dioxide emission reductions required to limit global warming to 2°C are becoming a receding goal based on new figures reported today in the latest Global Carbon Project (GCP) calculations published today in the advanced online edition of Nature Climate Change.

“A shift to a 2°C pathway requires an immediate, large, and sustained global mitigation effort,” GCP executive-director and CSIRO co-author of the paper, Dr Pep Canadell said.

Pep Canadell

Pep Canadell

Global CO2 emissions have increased by 58 per cent since 1990, rising 3 per cent in 2011, and 2.6 per cent in 2012. The most recent figure is estimated from a 3.3 per cent growth in global gross domestic product and a 0.7 per cent improvement in the carbon intensity of the economy.

Dr Canadell said the latest carbon dioxide emissions continue to track at the high end of a range of emission scenarios, expanding the gap between current trends and the course of mitigation needed to keep global warming below 2°C.

He said on-going international climate negotiations need to recognise and act upon the growing gap between the current pathway of global greenhouse emissions and the likely chance of holding the increase in global average temperature below 2°C above pre-industrial levels.

The research, led by Dr Glen Peters from CICERO, Norway, compared recent carbon dioxide emissions from fossil fuel combustion, cement production, and gas flaring with emission scenarios used to project climate change by the Intergovernmental Panel on Climate Change (IPCC).

“We need a sustained global CO2 mitigation rate of at least 3 per cent if global emissions are to peak before 2020 and follow an emission pathway that can keep the temperature increase below 2˚C,” Dr Peters said.

“Mitigation requires energy transition led by the largest emitters of China, the US, the European Union and India”.

He said that remaining below a 2°C rise above pre-industrial levels will require a commitment to technological, social and political innovations and an increasing need to rely on net negative emissions in future.

The Global Carbon Project, supported by CSIRO and the Australian Climate Change Science Program, generates annual emission summaries contributing to a process of informing policies and decisions on adaptation, mitigation, and their associated costs. The summaries are linked to long-term emission scenarios based on the degree of action taken to limit emissions.

Media: Craig Macaulay Ph: +61 3 6232 5219 Alt Ph: +61 4 1996 6465 E: Craig.Macaulay@csiro.au


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