Many of our plants and animals have adapted to fires, but now the fires are changing

Australia is a land that has known fire. Our diverse plant and animal species have become accustomed to life with fire, and in fact some require it to procreate.

But in recent decades the pattern of fires – also known as the fire regime – is changing. Individual fires are increasingly hotter, more frequent, happening earlier in the season and covering larger areas with a uniform intensity. And these changes to the fire regime are occurring too fast for our native flora and fauna to adapt and survive.

Read more: Some say we've seen bushfires worse than this before. But they're ignoring a few key facts

Our Fire-Adapted Plants Are Suffering

Many of Australia’s iconic eucalypts are “shade intolerant” species that adapted to exist within a relatively harsh fire regime. These species thrive just after a major fire has cleared away the overstory and prepared an ash bed for their seeds to germinate.

Some of our most majestic trees, like the alpine ash, can only regenerate from seed. Those seeds germinate only on bare earth, where the leaf litter and shrubs have been burnt away.

But if fire is so frequent the trees haven’t matured enough to produce seed, or so intense it destroys the seeds present in the canopy and the ground, then even these fire-adapted species can fail.

The current fires are re-burning some forests that were burnt only a decade ago. Those regenerating trees are too young to survive, but also too young to have started developing seed.

With the disappearance of these tree species, other plants will fill the gap. Acacias (wattles) are potential successors as they mature much earlier than alpine ash. Our tall, majestic forests could easily turn into shrubby bushland with more frequent fires.

Even within a burnt area, there are usually some unburnt patches, which are highly valuable for many types of plants and animals. These patches include gullies and depressions, but sometimes are just lucky coincidences of the terrain and weather. The patches act as reserves of “seed trees” to provide regeneration opportunities.

Recent fires, burning in hotter and drier conditions, are tending to be severe over large areas with fewer unburnt patches. Without these patches, there are no trees in the fire zone to spread seeds for regeneration.

Eucalypt seed is small and without wings or other mechanisms to help the wind disperse it. Birds don’t generally disperse these seeds either. Eucalypt seed thus only falls within 100 - 200 metres of the parent tree. It may take many decades for trees to recolonise a large burnt area.

That means wind-blown or bird-dispersed seeds from other species may fully colonise the burnt area well before the Eucalypts. Unfortunately many of these windblown seeds will be weed species, such as African Love Grass, which may then cover the bare earth and exclude successful Eucalypt regeneration while potentially making fires even hotter and more frequent.

Animals Have Fewer Places To Hide

Young animals are significantly more vulnerable to disturbances such as fire than mature individuals. So the best time to give birth is a season when fire is rare.

Spring in the southern zones of Australia has, in the past, been wetter and largely free from highly destructive fires. Both flora and fauna species thus time their reproduction for this period. But as fire seasons lengthen and begin earlier in the year, vulnerable nestlings and babies die where they shelter or starve as the fires burn the fruits and seeds they eat.

Australian fauna have developed behaviours that help them survive fire, including moving towards gullies and depressions, climbing higher, or occupying hollows and burrows (even if not their own) when they sense fire.

But even these behaviours will fail if those refuges are uncharacteristically burning under hotter and drier conditions. Rainforest, marshes and the banks of watercourses were once safe refuges against fire, but we have seen these all burn in recent fires.

Read more: Animal response to a bushfire is astounding. These are the tricks they use to survive

What Can Be Done?

All aspects of fire regimes in Australia are clearly changing as a result of our heating and drying climate. But humans can have a deliberate effect, and have done so in the past.

Indigenous burning created a patchwork of burnt areas and impacted on the magnitude and frequency of fires over the landscape. These regular burns kept the understory under control, while the moderate intensity and patchiness allowed larger trees to survive.

Read more: There's no evidence 'greenies' block bushfire hazard reduction but here's a controlled burn idea worth trying

There have been repeated calls of late to reintroduce Indigenous burning practices in Australia. But this would be difficult over vast areas. It requires knowledgeable individuals to regularly walk through each forest to understand the forest dynamics at a very fine scale.

More importantly, our landscapes are now filled with dry fuel, and shrubs that act as “ladders” - quickly sending any fire into tree canopies to cause very destructive crown fires. Given these high fuel conditions along with their potentially dangerous distribution, there may be relatively few safe areas to reintroduce Indigenous burning.

The changed fire conditions still require active management of forests, with trained professionals on the ground. Refuges could be developed throughout forests to provide places where animals can shelter and from which trees can recolonise. Such refuges could be reintroduced by reducing forest biomass (or fuel) using small fires where feasible or by mechanical means.

Biomass collected by machines could be used to produce biochar or other useful products. Biochar could even be used to improve the soil damaged by the fires and excess ash.

Midstory species could be cut down to prevent the development of fire ladders to tree crowns. Even the overstory could be thinned to minimise the potential for crown fires. Seed could also be collected from thinned trees to provide an off-site bank as ecological insurance.

Such active management will not be cheap. But using machinery rather than fire could control biomass quantity and distribution in a much more precise way: leaving some biomass on the ground as habitat for insects and reptiles, and removing other patches to create safer refuges from the fires that will continue to come.

Cris Brack, Associate Professor, Fenner School of Environment and Society, Australian National University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

How an Aussie invention could soon cut 5% of the world's greenhouse gas emissions

In the 1980s, a global race was underway: to find a more efficient way of converting energy from the sun into electricity.

Some 30 years ago, our research team at the University of New South Wales (UNSW) came up with a breakthrough, called the PERC silicon solar cell. The cells have become the most widely deployed electricity generation technology in terms of capacity added globally each year – comfortably exceeding wind, coal, gas, hydro and others.

Read more: Curious Kids: how do solar panels work?

PERC stands for Passivated Emitter and Rear Cell. By the end of this year, PERC technology will be mitigating about 1% of global greenhouse gas emissions by displacing coal burning. Assuming that its rapid growth continues, it should be reducing greenhouse gas emissions by 5% by the mid-2020s and possibly much more in later years.

The terrible bushfires in Australia this summer, enhanced by the hottest and driest year on record in 2019, underline the need for urgent reductions in greenhouse gas emissions. By far the most effective way is driving coal out of electricity systems through very rapid deployment of solar and wind.

Soon, our Aussie invention will be generating half the world’s solar power. It is a pertinent reminder of Australia’s capacity for finding transformative technical solutions to address climate change. But we need the right government support.

An Aussie Invention

Solar cells convert sunlight directly into electricity without moving parts. More efficient solar cells generally produce cheaper electricity because fewer solar cells, glass covers, transport, land and support structures are needed for a given solar power output.

By the early 1980s, the best laboratory cells around the world had reached 17% efficiency. This means that 17% of the sunlight was converted to electricity, and the rest (83%) of the solar energy was lost (as heat).

During the 1980s, our research team at UNSW led by Martin Green and myself created a series of world-record-efficient silicon solar cells. We reported 18% efficiency in 1984, 19% efficiency also in 1984, and the important milestone of 20% efficiency in 1986.

Read more: Some good news for a change: Australia's greenhouse gas emissions are set to fall

In 1989 our group reported a new solar cell design called “PERC”, with a record efficiency of 22-23%.

This new, more efficient cell was better than the old ones because we eliminated some defects in the silicon crystal surface, which led to lower electronic losses. The PERC design also enabled us to capture the sunlight more effectively.

In the 1990s, further improvements to laboratory PERC cells were made at UNSW, leading to cells in the 24-25% efficiency range. The global silicon solar cell efficiency record remained at UNSW until recently.

There was a 25-year gap between development of the PERC cell and its rapid commercial adoption, which began in 2013. During this time, many people worked to adapt the PERC design to commercial production.

PERC cells are more efficient than previous commercial cells. Strong incentives for more efficient cells have recently arisen due to the continually falling share of cell costs as a proportion of total solar power system costs (including transport, land and mounting systems).

The Big Benefits Of Solar

Currently, solar power constitutes more than 40% of net new electricity generation capacity additions, with fossil, nuclear, wind, hydro and other renewables making up the balance.

Solar is growing faster than the other electricity generation technologies. Over time, as fossil-fuelled power stations are retired, solar (and wind) will dominate electricity production, with consequent large reductions in greenhouse gas emissions.

This year, enough PERC solar modules will be sold to generate 60-70 gigawatts of power. According to projections, PERC will reach three quarters of annual solar module sales in the mid-2020s, enough to match the generation capacity additions from all other technologies combined.

About A$50 billion worth of PERC modules have been sold to date. This is expected to reach several hundred billion Australian dollars later this decade.

Just Imagine

Australian emissions (excluding those from bushfires) are falling because we are installing solar and wind four times faster per capita than the EU, US, Japan and China.

Our position as a global leader in renewables installation is uncertain because the Renewable Energy Target, which was achieved in 2019, has not been extended.

Read more: Weather bureau says hottest, driest year on record led to extreme bushfire season

With supportive policy, such as facilitating more transmission to bring solar and wind power to the cities, Australia could greatly increase the speed at which wind and solar are deployed, yielding rapid and deep cuts at about zero-net cost.

Such policy would entail stronger and sustained government support for renewables deployment, and research and development of new technologies.

Looking Ahead

Solar energy is vast, ubiquitous and indefinitely sustainable. Simple calculations show that less than 1% of the world’s land area would be required to provide all of the world’s energy from solar power – much of it on building roofs, in deserts and floating on water bodies.

Solar systems use only very common materials (we could never run out), have minimal need for mining (about 1% of that needed for equivalent fossil or nuclear fuels), have minimal security and military risks (we will never go to war over solar access), cannot have significant accidents (unlike nuclear), and have minimal environmental impact over unlimited time scales.

Australia is making major contributions to mitigating climate change both through rapid deployment of wind and solar and technology development such as our PERC cells. But with better government support, much more can be done – quickly and at low cost.

Andrew Blakers, Professor of Engineering, Australian National University

This article is republished from The Conversation under a Creative Commons license. Read the original article.