The headline message from the recently released IPCC 5th Assessment Report (Climate change 2013: The Physical Science Basis ^[1]) is pretty straightforward:

Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased.

Concentrations of carbon dioxide and other greenhouse gasses in the atmosphere are now at levels not achieved in at least the last 800,000 years, as recorded in ice cores. The oceans, which have absorbed about one third of the human produced carbon dioxide since the industrial revolution, are now becoming more acidic.

The various greenhouse gas emission scenarios used in the IPCC report show that if emissions continue along a ‘business as usual’ trajectory, global temperature could rise between at least 3.2°C and 5.4°C above the 1850 to 1890 baseline by 2100. Keeping temperature rises below 2°C will require a considerable global effort to reduce greenhouse gas emissions and/or sequester carbon. Warming will continue beyond the end of the century, unless emissions are dramatically curtailed, and, for example, sea levels will continue to rise for decades and centuries beyond that. But at this stage there’s no sign that a comprehensive and binding international agreement to cut emissions of greenhouse gases is close.

The globe won’t warm ‘evenly’, and changes to rainfall patterns won’t be uniform. There’ll be greater contrast between dry regions and wet regions and also between seasons—but more research is required to see how these patterns will emerge region by region.

Australia’s regional security interests stretch from the tropics to the Antarctic and across three oceans. A changing climate has ramifications for all of our Defence efforts: operations, response, training, planning, preparedness and engagement. There’s some degree of recognition of this in the 2013 Defence White Paper (see, for example, paras 2.72 to 75). What’s needed now, however, is a real commitment to coordinated and sustainable action.

The ADF should reduce non-operational emissions, (e.g. by reducing its use of petroleum products, setting specific energy targets) and improve its overall approach to sustainability practices, for example by using renewables at bases. Work that’s now underway in elements of Defence to address a range of energy related challenges might benefit from a more integrated approach.

We understand that Defence is evaluating the security risks posed by a warming planet, (looking at the environmental impacts its own activities are having, and developing adaptation and energy plans for its ‘at risk’ facilities). But, again, there’s a greater need for coordinated action across the Defence portfolio.

In order for Defence to become as prepared as possible for the risks of climate change, it should appoint a high level officer, ideally situated with the strategic defence headquarters, to coordinate climate-related planning and action across the ADF.

That officer could examine the impacts of climate change on operations, facilities, and energy usage and foster inter-departmental cooperation and could coordinate Defence’s engagement with climate scientists. Raising the impacts of climate change as an issue for Defence in this way should stimulate climate change planning across the ADF.

We’d underline the importance of Defence partnering with other Commonwealth agencies on cross cutting climate issues, our ‘five eyes’ partners and regional states in tackling some of the key climate challenges both at home (e.g. impacts on infrastructure and training areas) and in the region.

It’d be naïve to suggest that climate change should be the number one priority for the ADF and the Defence department: Defence won’t and shouldn’t be the Australian lead agency on climate change. But the findings of the latest IPCC report underline the need for Defence to factor in climate change into many aspects of its planning and to play a constructive role with other parts of government in mitigation and adaption. In that respect, it’s encouraging to see that former CDF Admiral Chris Barrie has become a member of the Global Military Advisers on Climate Change ^[2] organisation, a subsidiary of the Institute of Environmental Security based in The Hague.

Anthony Press is the CEO of the Antarctic Climate and Ecosystems Cooperative Research Centre. Anthony Bergin is deputy director of ASPI. They are the co-authors (with Eliza Garnsey) of Heavy weather: climate and the Australian Defence Force. ASPI Special Report, March 2013 ^[3].