Was Tasmania’s summer of fires and floods a glimpse of its climate future?


Alistair Hobday, CSIRO; Eric Oliver, University of Tasmania; Jan McDonald, University of Tasmania, and Michael Grose, CSIRO

Drought, fires, floods, marine heatwaves – Tasmania has had a tough time this summer. These events damaged its natural environment, including world heritage forests and alpine areas, and affected homes, businesses and energy security.

In past decades, climate-related warming of Tasmania’s land and ocean environments has seen dozens of marine species moving south, contributed to dieback in several tree species, and encouraged businesses and people from mainland Australia to relocate. These slow changes don’t generate a lot of attention, but this summer’s events have made people sit up and take notice.

If climate change will produce conditions that we have never seen before, did Tasmania just get a glimpse of this future?

Hot summer

After the coldest winter in half a century, Tasmania experienced a warm and very dry spring in 2015, including a record dry October. During this time there was a strong El Niño event in the Pacific Ocean and a positive Indian Ocean Dipole event, both of which influence Tasmania’s climate.

The dry spring was followed by Tasmania’s warmest summer since records began in 1910, with temperatures 1.78℃ above the long-term average. Many regions, especially the west coast, stayed dry during the summer – a pattern consistent with climate projections. The dry spring and summer led to a reduction in available water, including a reduction of inflows into reservoirs.

Left: September-November 2015 rainfall, relative to the long-term average. Right: December 2015-February 2016 temperatures, relative to the long-term average.
Bureau of Meteorology, Author provided

Is warmer better? Not with fires and floods

Tourists and locals alike enjoyed the clear, warm days – but these conditions came at a cost, priming Tasmania for damaging bushfires. Three big lightning storms struck, including one on January 13 that delivered almost 2,000 lightning strikes and sparked many fires, particularly in the state’s northwest.

By the end of February, more than 300 fires had burned more than 120,000 hectares, including more than 1% of Tasmania’s World Heritage Area – alpine areas that had not burnt since the end of the last ice age some 8,000 years ago. Their fire-sensitive cushion plants and endemic pine forests are unlikely to recover, due to the loss of peat and soils.

Meanwhile, the state’s emergency resources were further stretched by heavy rain at the end of January. This caused flash flooding in several east coast towns, some of which received their highest rainfall ever. Launceston experienced its second-wettest day on record, while Gray recorded 221 mm in one day, and 489 mm over four days.

Flooding and road closures isolated parts of the state for several days, and many businesses (particularly tourism) suffered weeks of disruption. The extreme rainfall was caused by an intense low-pressure system – the Climate Futures for Tasmania project has predicted that this kind of event will become more frequent in the state’s northeast under a warming climate.

Warm seas

This summer, an extended marine heatwave also developed off eastern Tasmania. Temperatures were 4.4℃ above average, partly due to the warm East Australian Current extending southwards. The heatwave began on December 3, 2015, and was ongoing as of April 17 – the longest such event recorded in Tasmania since satellite records began in 1982. It began just days after the end of the second-longest marine heatwave on record, from August 31 to November 28, 2015, although that event was less intense.

Anatomy of a marine heatwave. Top left: summer sea surface temperatures relative to seasonal average. Top right: ocean temperature over time; red shaded region shows the ongoing heatwave. Bottom panels: duration (left) and intensity (right) of all recorded heatwaves; the ongoing event is shown in red.
Eric Oliver

As well as months of near-constant heat stress, oyster farms along the east coast were devastated by a new disease, Pacific Oyster Mortality Syndrome, which killed 100% of juvenile oysters at some farms. The disease, which has previously affected New South Wales oyster farms, is thought to be linked to unusually warm water temperatures, although this is not yet proven.

Compounding the damage

Tasmania is often seen as having a mild climate that is less vulnerable to damage from climate change. It has even been portrayed as a “climate refuge”. But if this summer was a taste of things to come, Tasmania may be less resilient than many have believed.

The spring and summer weather also hit Tasmania’s hydroelectric dams, which were already run down during the short-lived carbon price as Tasmania sold clean renewable power to the mainland. Dam levels are at an all-time low and continue to fall.

The situation has escalated into a looming energy crisis, because the state’s connection to the national electricity grid – the Basslink cable – has not been operational since late December. The state faces the prospect of meeting winter energy demand by running 200 leased diesel generators, at a cost of A$43 million and making major carbon emissions that can only exacerbate the climate-related problems that are already stretching the state’s emergency response capability.

Is this summer’s experience a window on the future? Further study into the causes of climate events, known as “detection and attribution”, can help us untangle the human influence from natural factors.

If we do see the fingerprint of human influence on this summer, Tasmania and every other state and territory should take in the view and plan accordingly. The likely concurrence of multiple events in the future – such as Tasmania’s simultaneous fires and floods at either end of the island and a heatwave offshore – demands that governments and communities devise new strategies and mobilise extra resources.

This will require unprecedented coordination and cooperation between governments at all levels, and between governments, citizens, and community and business groups. Done well, the island state could show other parts of Australia how to prepare for a future with no precedent.

The Conversation

Alistair Hobday, Senior Principal Research Scientist – Oceans and Atmosphere, CSIRO; Eric Oliver, Postdoctoral Fellow (Physical Oceanography and Climate), University of Tasmania; Jan McDonald, Professor of Environmental Law, University of Tasmania, and Michael Grose, Climate Projections Scientist, CSIRO

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

Phasing out fossil fuels for renewables may not be a straightforward swap


Anthony James, Swinburne University of Technology

To have any chance of preventing dangerous climate change, the world needs to reduce greenhouse gas emissions to net zero or even negative by mid-century. Many experts suggest this means we need to completely phase out fossil fuels and replace them with renewable energy sources such as solar and wind.

Several studies have concluded that 100% renewable energy supply systems are technically and economically feasible. This informs the widespread view that fossil fuels can be more or less “swapped out” for renewables, without significant economic consequences.

We are strongly sympathetic to the need for a rapid global shift away from fossil fuels. But new modelling conducted independently and made publicly available by my colleague at the Understandascope, Josh Floyd, suggests that such a transition may face significant challenges.

Future energy

Analyses of how to get to 100% renewable energy typically look at how future energy sources can supply enough energy to meet a given future demand.

This is what’s known as an “energy balance”. The high-quality work of Mark Diesendorf and his colleagues on the transition of Australia’s electricity supply to 100% renewables typifies such modelling.

But this approach doesn’t tell us what will happen to overall energy supply during the transition.

This new modelling suggests a significant decline in availability of overall energy services during the transition phase. This reflects the increased energy demand associated with the transition task itself.

Such an energy “trough” would significantly impact the economy during the transition. This has flow-on consequences for how to maintain the massive renewables roll-out.

What are net energy services?

To investigate what might happen to energy availability during transition, the model looks at “net energy services” at a global scale.

Net energy services are the total work and heat that energy sources – for instance solar photovoltaic (PV) systems or petroleum – make available to end users, minus the energy services required to provide that supply.

Petroleum requires energy services to find, produce, transport and refine it. Solar PV systems require energy services for mining raw materials, manufacturing, installation, replacement and so on. The net services are what remains available for all other purposes, such as heating buildings and moving goods and people.

A rapid, large-scale energy transition creates extra demands for energy services. This demand will compete with other economic activity.

The speed of transition matters

To start with, the model assumes that fossil fuels are phased out over about 50 years. Biomass, hydro and nuclear contributions are assumed roughly to double.

The model then attempts to maintain the net energy services to the global economy at the maximum level before the fossil fuel phase-out. To do this it uses electricity from onshore wind turbines and large-scale solar PV plants, buffered with lithium ion batteries.

The findings show that the faster the transition rate, the greater the energy services required by the transition task, and the lower the services available for other uses.

This is because of the time lag between energy investments and returns. It is exacerbated for sources where up-front energy investment is a relatively high proportion of the total life cycle, particularly so for solar PV.

A 50-year fossil-fuel phase-out represents a relatively modest transition rate. Even so, in the model’s baseline scenario, net energy services decline during that transition period by more than 15% before recovering.

And that recovery is not certain. The model doesn’t consider how this decline in energy services might affect the transition effort. If less energy services are available, then energy transition will come at the expense of other economic activity. That may impact the collective will to continue.

The cost of transition

In the model’s baseline scenario – phasing out fossil fuels over 50 years – wind and solar plants need to be installed at eight to ten times current rates by 2035.

Financially, this corresponds with capital investment in wind and solar PV plants plus batteries of around US$3 trillion per year (in 2015 dollars) and average lifetime capital cost in the order of US$5 trillion to US$6 trillion per year.

For comparison, in 2014 the International Energy Agency forecast global investment for all energy supply in 2035 at US$2 trillion per year.

This implies that total expenditure on energy supply will increase its share of world spending, reducing scope for other expenditure. Compounding the decline in energy services during transition, this has potential to apply contractionary pressure to the global economy. This has implications in turn for financing and maintaining the political will for the renewables rollout.

What if it were possible to roll out renewables even faster? This could reduce the depth and duration of the decline, but not eliminate it. Again, due to the time lags involved, accelerating deployment in the short term takes energy services away, rather than adding them.

What does this mean?

Of course, this is “just” modelling. But good models can tell us a lot about the real world. If this modelling is right, and energy services fall and costs rise, we’ll have to complement building cleaner energy supply with other approaches.

The other key aspect of transition that we have control over is how much energy we expect to use. Usually discussions of transition focus on maintaining energy supply sufficient for a growing economy much like we see today – just with “clean” energy. But this is changing.

Growing numbers of analysts, business leaders and other prominent figures are calling for broader cultural change, as it becomes clearer that technological change alone is not enough to avoid climate catastrophe and myriad other consequences of energy-intensive consumer societies.

This is about more than efficiency. It is about a shift in our collective priorities and how we define progress, wellbeing and quality of living. Reducing energy demand within these redefined aspirations will markedly improve our prospects for successful transition.

This article was co-authored by Josh Floyd, advisor on energy, systems and societal futures at independent research and education organisation the Understandascope, and founding partner of the Centre for Australian Foresight.

The Conversation

Anthony James, Lecturer with the National Centre for Sustainability , Swinburne University of Technology

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