Learning to adapt to future climates
What are we adapting to?
Australia's climate is already changing
In the last 50 years, we’ve seen less rain in southern and eastern Australia, more frequent heatwaves, fewer frosts, an increase in the intensity of drought, and a small rise in sea level. Many people have noticed the impact of these changes in their daily lives, through things like water restrictions, higher prices for fresh food, flowers blooming earlier in the season, and regular stories of extreme weather events on the nightly news.
Climate change will continue for many decades, because there’s a time-lag between when emissions occur, and when their consequences are felt. For example, it’s now clear that the increase in global average temperatures that we’ve experienced since the 1950s is very likely due to the sharp increase in greenhouse gas emissions that began over 150 years ago, with the industrial revolution.
In the same way, the high level of global greenhouse gas emissions occurring today means we are ‘locked in’ to continued climate change in the coming decades. That’s why scientists now talk about the need to adapt to ‘unavoidable’ climate change.
Climate change will continue for many decades, because there’s a time-lag between when emissions occur, and when their consequences are felt.
What is unavoidable climate change?
Even if all human greenhouse gas emissions stopped immediately, the world would be committed to some ongoing changes in the climate. This is due to the time lag as carbon dioxide follows its natural cycle through atmosphere, ocean and land systems. The additional amount of greenhouse gases released into the atmosphere as a result of human activities over the last century or more are slowly filtering through the oceans and the now decreasing forests.
The changes in the Australian climate projected for 2030 are mostly due to greenhouse gases that have already been released, which means they are considered to be unavoidable.
Projections for Australia in 2030 include:
- 1° C increase in average temperature, compared to 1990
- more very hot days, fewer frosts
- decrease in rainfall in southern Australia
- more months of drought
- greater bushfire risk in south-east Australia
- an increase in the intensity of cyclones
- more hail events along the New South Wales coast, on average per year
- larger areas at risk of inundation from storm surges
- early signs of ocean acidification in Queensland.
As we look further into the future, the amount of climate change depends partly on the influence of historic greenhouse gases emissions, and partly on the level of future emissions over the coming decades.
How much adaptation will be needed?
Delays in the global effort to reduce greenhouse gas emissions due to social, political, and technological barriers pose significant risk that needs to be factored into climate adaptation planning.
To date, global emission levels are increasing, not decreasing, and that increase is speeding up. Policy makers must weigh up the costs of reducing emissions against the costs of future impacts and adaptation. Effects will not occur evenly as a global average temperature increase of 4° C will mean a 6° C increase in Australia.
The more we reduce emissions now, the less climate change we will need to adapt to in future, and vice versa.
Limits to adaptation
It will not always be possible to adapt to changes in the climate, and it is clear that there are many limits to adaptation. This is particularly evident in the natural environment, where many plants and animals face a serious risk of extinction due to climate change.
Some of the major changes in weather patterns, extreme weather events, ocean acidification, and sea level rise that are possible under a 4° C global increase would have severe negative impacts including extensive loss of life and assets. In situations where there is no known way to adapt to a potential climate impact, addressing the source of the threat by controlling greenhouse gas emissions is the only feasible option.
Dealing with uncertainty
For many people, one of the most challenging things about climate adaptation is grappling with uncertainties about what the climate will be like in the future.
The current level of scientific understanding of the likely consequences of climate change is strong. We have access to sophisticated climate models that can provide climate projections to inform decision making. However, none of us has a crystal ball - it’s impossible to say with 100 per cent certainty exactly what the impacts of climate change will be in a particular location, or precisely when they will occur.
The main sources of uncertainty include:
- current limits and gaps in our scientific understanding of the earth-climate system, for example: how rapidly will ice-caps melt and how much sea level rise will this cause?
- the complexity of modelling the global climate system, for example: how will warmer temperatures influence ocean currents and El Nino?
- the inherent difficulty of predicting human behaviour, for example: how fast will developing economies grow and how will this affect their emissions of greenhouse gases?
- the challenge of ‘down-scaling’ climate projections to provide robust predictions of how global climate change will influence local weather patterns.
Uncertainty is nothing new
Every day, governments, businesses, and individuals make important decisions in the absence of complete information. Adapting to climate change is no different; we must inform ourselves with the best available information, weigh up the risks, costs and benefits, and decide on a course of action.
Any local or sectoral vulnerability assessment or adaptation plan needs to carefully assess the relevant issues and uncertainties, and where possible, commission tailor-made climate projections that focus on the most relevant impacts and provide detailed local predictions.