The IPCC WGII Sixth Assessment Report has just been released (and is available here).
The take home message is:
Further climate change is inevitable, with the rate and magnitude of impact largely dependent on the emission reduction pathways that we choose. Time is running out if we want to act.
The final sentence of new IPCC report is: “The scientific evidence is unequivocal: climate change is a threat to human well-being and the health of the planet. Any further delay in concerted global action will miss a brief and rapidly closing window to secure a liveable future.”
The Chapter on Australasia (available here) has a considerable amount of detail on likely impacts on mountain areas of south eastern Australia and lutruwita/ Tasmania. Some of these are summarised below. It looks at both observed impacts and predicted future impacts (applying a level of certainty to each of these).
In Australia, temperatures have increased by 1.4°C from 1910–2019. 2019 was the warmest year, and nine of the ten warmest on record occurred since 2005. There is clear anthropogenic attribution to this (ie, human driven climate change is making the planet hotter).
Ongoing climate trends have exacerbated many extreme events (very high confidence). The Australian trends include further warming and sea-level rise, with more hot days and heatwaves, less snow, more rainfall in the north, less April-October rainfall in the south-west and south-east, more extreme fire weather days in the south and east.
Climate trends and extreme events have combined with exposure and vulnerabilities to cause major impacts for many natural systems, with some experiencing or at risk of irreversible change in Australia (very high confidence) and in New Zealand (high confidence). For example, warmer conditions with more heatwaves, droughts and catastrophic wildfires have negatively impacted terrestrial and freshwater ecosystems.
Less winter and spring rainfall is projected in southern Australia, with more winter rainfall in Tasmania, less autumn rainfall in south-western Victoria and less summer rainfall in western Tasmania (medium confidence)
- The extreme fire weather experienced in 2019-2020 was at least 30% more likely due to climate change.
- More droughts and extreme fire weather are projected in southern and eastern Australia (high confidence)
- There was an increase in the number of extreme fire weather days from July 1950 to June 1985 compared to July 1985 to June 2020, especially in the south and east, partly attributed to climate change.
- There have been more dangerous conditions for extreme pyro convection events since 1979, particularly in south-eastern Australia.
Multiple wildfires in short succession are resulting from increased fire risk conditions including declining winter rainfall
Increase in lightning-ignited landscape fires along with contracting palaeoendemic refugia due to warmer and drier climates. This has resulted in population collapse and severe range contraction of slow-growing, fire- sensitive palaeoendemic temperate rainforest species (e.g. Pencil Pine).
Severe winter drought mean will mean shifts in dominant vegetation with a decline in grasses and other graminoids and an increase in forb and shrub cover in areas like the Bogong High Plains.
There will be changing interactions within and among three key alpine taxa related to food supply and vegetation habitat resources: The mountain pygmy-possum (Burramys parvus), the mountain plum pine (Podocarpus lawrencei) and the bogong moth (Agrostis infusia).
Retreat of snow line will mean increased species diversity in alpine zone.
Reduced snow cover will lead to loss of snow-related habitat for alpine zone endemic and obligate species.
In southern Australia, some forest ecosystems (alpine ash, snowgum woodland, pencil pine, northern jarrah) are projected to transition to a new state or collapse due to hotter and drier conditions with more fires.
Over the past 30 years, drought-induced canopy dieback across a range of forest and woodland types, and death of fire-sensitive tree species due to unprecedented wildfires has occurred.
Snow Gums and Alpine Ash
There is risk of transition or collapse of alpine ash and snowgum woodland, due to hotter and drier conditions with more fires
If regenerative capacities of the dominant canopy tree species are exceeded, a long lasting or irreversible transition to a new ecosystem state is projected, with loss of characteristic and framework species including loss of some narrow range
Hazards: Hotter and drier conditions have increased extreme fire weather risk since 1950, especially in southern and eastern Australia. The number of severe fire weather days is projected to increase 5-35% (under RCP2.6 scenario – see below) and 10-70% (RCP8.5) by 2050.
The RCP2. 6 emission and concentration pathway is representative of the literature on mitigation scenarios aiming to limit the increase of global mean temperature to 2°C. A sizeable portion of recent studies on future climate impacts have focused on a warming scenario called “RCP8. 5”. This high-emissions scenario is frequently referred to as “business as usual”, suggesting that is a likely outcome if society does not make concerted efforts to cut greenhouse gas emissions.
The shift in landscape fire regimes to larger, more intense and frequent wildfires over extensive areas (~10 million hectares) of forests and woodlands from longer fire seasons and more hazardous fire conditions and projected increase in frequency of lightning strikes
How do we respond?
According to the IPCC there are some ‘adaptation’ options:
- Increased capacity to extinguish wildfires during extreme fire weather conditions;
- avoiding and reducing forest degradation from inappropriate forest management
practices and land use.
Snowpack has been in decline for decades in Australia (check here for extra details).
At Spencers Creek (NSW), annual maximum snow depth decreased 10% and the length of the snow season decreased 5% during 2000–2013 relative to 1954–1999.
At Rocky Valley Dam (1650 m elevation) in Victoria, annual maximum snow depth decreased 5.7 cm/decade from 1954- 2011. At Mt Hotham, Mt Buller and Falls Creek (1638-1760 m elevation), annual maximum snow depth decreased 15 %/decade from 1988-2013.
There will be an Increase in heat-related mortality and morbidity for people and wildlife in Australia due to heatwaves.
There will be Cascading, compounding and aggregate impacts on cities, settlements, infrastructure, supply-chains and services due to wildfires, floods, droughts, heatwaves, storms.
Tourism has been negatively affected by coral bleaching, fires, poor ski seasons and receding glaciers.
Australia’s ski industry is very sensitive to climatic change, due to reduction in snow depth and the length of the snow season.
Widespread impacts from projected climate change are very likely across the tourism sector.
Snow skiing faces significant challenges from climate change (high confidence). In Australia, the annual maximum snow depth is estimated to decrease from current levels by 15% (2030) and 60% by 2070. By 2070-2099, relative to 2000-2010, the length of the Victorian ski-season is projected to contract by 65-90% under RCP8.5
Current snow-making technologies are expected to sustain the ski industry until mid-century. However, with warmer winter temperatures and declining water availability, snow-making is projected to decrease to half at most resorts by 2030.
What can we do about this?
The first thing is to radically reduce our contribution to further global heating.
When it comes to fighting fire, we need to intervene to keep Snow Gum woodland communities viable, in the way we have with Alpine Ash. But instead of aerial seeding, it would appear that the best thing we can do is to keep fire out of these communities as they recover from fire. That will take planning, a commitment to actively prioritise these forests in high risk summers, and resourcing.
Here are some ideas.
A remote area volunteer firefighting team for Victoria
This is a proposal to develop a new volunteer firefighting force specifically tasked with adding capacity to state government firefighting agencies when fires threaten national parks, wilderness and World Heritage Areas.
A national remote area firefighting team
This was recommended by a Senate inquiry after the devastating fires in Tasmania of 2016.
National crews cannot be expected to know the terrain of the Victorian Alps in the way that local remote area teams will. But such a national team could provide welcome additional support to locals in extreme summers.
Additional air and first attack capacity
Aircraft and helicopters are essential components of modern firefighting. They are used to carry water and retardant to drop of fires, for intelligence gathering and air supervision, and moving firefighters and other staff.
Australia’s National Aerial Firefighting Centre contracts a fleet of 150 firefighting aircraft across all states and territories, which goes up to 500 when including “on call” vehicles. At the beginning of the 2019-20 season, five large air tankers and nine large helicopters were contracted from North America, but as fires worsened in November, two additional tankers were leased. By January, $20 million in additional funding from the Australian government was used to add four more, including a DC-10 Air Tanker flown from Alabama thought to have cost AUD$1 million for the 50 days of its contract (Source).
The dilemma is that as our fire seasons get longer (potentially going from September to late March), the same thing is happening elsewhere in the world.
A smart option is to purchase additional aircraft so we are not locked into a market where the price of contract rentals keeps escalating. This is the responsibility of the federal government.
For further information on the proposal for a publicly owned air fleet, please check here.
Please take action
A simple thing you can do is to sign this letter to the Victorian Environment Minister, urging her to act to protect Snow Gum communities.
The letter calls for:
- A rapid ecological assessment of the threats posed by fire and dieback to Snow Gum communities.
- Ongoing funding for Forest Fire Management Victoria, including additional funding for remote area firefighting teams.
- Continued support for air capacity to fight fires, including establishing a publicly owned air fleet, as was recommended by the Bushfire Royal Commission. This is the responsibility of the federal government.
- Creation of volunteer remote area firefighting teams, as NSW, the ACT and Tasmania have done.
- A commitment to ensure we have sufficient fire fighting resources to protect fire sensitive communities like Alpine Ash, Snow Gums, Alpine Peatlands and Rainforest even during summers like 2019/20.
You can find out more about threats to the Victorian high country in this report.