This latest report comes halfway through the Critical Decade for climate action and four years after the Climate Commission released its report, ‘Critical Decade: Climate science, risks and responses’. The report outlines how the changing climate poses substantial and escalating risks for health, property, infrastructure, agriculture and natural ecosystems in Australia.
Compared to our understanding when the last Critical Decade report was published, the risks of climate change for our wellbeing now look more serious at lower levels of climate change, strengthening the case for urgent action.
Our understanding of climate change continues to strengthen, with dramatic changes of the climate system happening across the globe.
- It is beyond doubt that human activities, primarily the emission of greenhouse gases from the combustion of fossil fuels like coal, oil and gas, are driving the dramatic changes of the climate system.
- Climate change is increasing the frequency and severity of many extreme weather events, including heatwaves and extreme bushfire conditions.
- Hot days have doubled in the last 50 years, while heatwaves have become hotter, last longer and occur more often.
- Over the last 30 years extreme fire weather has increased in the populous southeast region of Australia - southern NSW, Victoria, Tasmania and parts of South Australia.
- Extreme sea-level events tripled at Sydney and Fremantle over the 20th century.
The changing climate poses substantial and escalating risks for health, property, infrastructure, agriculture and natural ecosystems.
- Further increases in extreme heat in Australia are likely with more frequent and more intense hot days and longer and more severe heatwaves. Deaths from heatwaves are projected to double over the next 40 years in Australian cities.
- More than $226 billion in commercial, industrial, road, rail and residential assets around Australian coasts, most of them in urban areas, are potentially exposed to flooding and erosion hazards at a sea-level rise of 1.1 m.
- From 2020 onwards, the predicted increase in drought frequency is estimated to cost $7.3 billion annually, reducing GDP by 1% per year.
- If global temperatures reach 3°C above pre-industrial levels, an estimated 8.5% of species globally are at risk of extinction, and under a “business as usual” scenario, leading to global warming of 4°C or more, a staggering one in six species could be lost.
The risks of climate change for our well-being now look more serious at lower levels of climate change, strengthening the case for urgent action.
- Changes in the climate system are occurring more rapidly than previously projected with larger and more damaging impacts now observed at lower temperatures than previously estimated.
- The scientific underpinning for the 2°C policy target being a “safe” level of climate change is now weaker than it was a decade ago. The scientific case for a 1.5°C limit is more consistent with our current level of understanding, bolstering the case for even more urgent action.
- As the global average temperature rises further above the pre-industrial level, so does the risk of crossing thresholds or tipping points in the climate system, such as the loss of the Greenland ice sheet, the partial conversion of the Amazon rainforest to a savanna or grassland, and the large-scale emission of carbon dioxide (CO2) and methane from thawing permafrost. Crossing these thresholds would cause further disruptions to the climate system, with potentially catastrophic knock-on effects for human societies.
The action we take in the next five years will largely determine the severity of climate change and its long-term impact on human societies. While action is building worldwide, Australia is lagging behind.
- It is in Australia’s national interest to tackle climate change, as a country on the front line of climate change impacts and as one of the world’s largest per capita emitters of greenhouse gases.
- There is growing global action to tackle climate change with the rapid uptake of solutions, such as renewable energy, and countries are pledging stronger emissions reduction targets.
- Australia is out of step with the rest of the developed world in climate action; by any indicator used to measure level of effort, Australia is at or near the bottom of the list of developed countries.
- A very strong and rapid decarbonisation of the global economy could stabilise the climate system below 2°C, while a business-as-usual scenario could lead to temperature rises of 4°C or above by the end of the century, threatening the viability of modern society