Review by Geoff Brooks, WPB Foundation Director
The Intergovernmental Panel on Climate Change (IPCC) released its latest scientific report on the actual and projected changes for the global climate in August with some very clear messages.
Change is occurring rapidly and humans are significant contributors. In fact, the impact of carbon emissions from human activity will be amplified in the years ahead, unless we make radical changes to the speed with which we tackle them.
For a top-level perspective of what the IPCC modelling reveals, we suggest you read the Summary for Policy Makers document, an extract from the entire report, whose scientific data and analysis stretches over 3000 pages.
With a large proportion of the world committed to achieving net zero carbon dioxide (CO2) emissions by 2050, including some Australian states, we believe this is the minimum policy setting required to address this issue, given the IPCC findings. The cost of not doing so will be enormous and largely borne by future generations.
There are many complexities and levels of confidence about the IPCC projections and sceptics will no doubt highlight areas of low to medium confidence in which there is scope for most debate.
Whatever the quantum of change (and the IPCC’s modelling covers a range of possibilities from a relatively mild 1.5oC increase to the middle of the century to around 5oC), the trends are clear – higher global temperatures, rising sea levels, more extreme climatic events like floods and drought, and wide-ranging consequences for the environment and the way we interact with it.
The changes outlined in the IPCC’s global projections will naturally have ramifications for the delicate environmental balance within the Western Port Biosphere Reserve. Here are some of the key areas:
The modelling predicts a drier climate for south-east Australia at both the low and high ends of expected global temperature increases.
Our climate will also be more volatile and less predictable, experiencing more extremely hot days. This will make life tougher for everyone, including those involved in agriculture. It is a trend already begun, as shown in this graphic from the CSIRO.
Water stewardship will become more important, both to conserve the resource and manage outflows into our bays. Some farmers will need to consider the viability of some crops and possibly switch to drought resistant varieties.
2. Marine Changes
It may seem contradictory to talk about a drier climate and rising sea levels, but the rising sea levels in and around Western Port will be driven by change far removed from us. From 1971 to 2018, 50% of sea level rise was attributable to thermal expansion, in other words increased volume of water due to general temperature rise. However, in the last 12 years of that period, volume increase from melting glaciers and ice sheets accounted for more than half of sea level rise.
The implications for Western Port could be significant, with the bay’s ability to maintain something like its current form governed by the rates at which mangroves and seagrasses can adjust to sea level rises. These species are also important in mitigating increases in acidification and deoxygenation (lower oxygen levels) of seawater. Seagrasses in particular, have a capacity substantially greater than similar tracts of rainforest to absorb carbon dioxide.
According to a 2011 joint report ‘Understanding the Western Port Environment’ by Melbourne Water, the Port Phillip and Western Port Catchment Management Authority and the Victorian Government though, it is not known how much these trends will impact Western Port.
In both instances, any adjustment can be further challenged by poorly planned human development of coastline and waterways.
The IPCC modelling uses multiple metrics for calculating the possibility of drought over periods of a decade. The most influential of these are soil moisture level and water balance i.e. water retained in the environment after evaporation and other loss.
For some reason, the IPCC reports there is limited data for Australia, one of the world’s most drought prone countries. However, it does expect increased frequency of drought for southern Australia. It emphasises its broader finding that our region will be drier by suggesting that we can expect it to also be drier for longer over any given 10-year period.
On a positive note, the IPCC notes that there is still time and scope for humanity to make changes that can mitigate against the worst climatic outcomes. It is still within our hands to ensure any climate change is constrained to a minimum and to a rate of change which gives our environment a fighting chance to adjust.
Doing this will require the cumulative effort of communities around the globe, making adjustments to lifestyle, consumption and waste management, while ensuring we plan future development that takes into account the environment pressures we face.
If we act with conviction and at scale now, the IPCC anticipates that we could feel climate reversal in our daily lives within about 30 years. The Western Port Biosphere Foundation is already acting, with a water stewardship program to help business and communities reduce consumption, recycle and manage this critical resource. We play a central role in building awareness of our Ramsar protected wetlands and how by protecting them we can support biodiversity and environmental health.
Unfortunately, some of the outcomes of historical inaction are already baked in, but the IPCC scientists warn that further inaction, or even under-action will result in transformative changes to our terrestrial and marine environments, such as sea level rise, will not be reversible ‘within centennial or even millennia timeframes’.
Prevention is clearly better than cure.