The Intergovernmental Panel on Climate Change has released its latest authoritative assessment of climate change science, delivering a stark warning to the world that climate change is already occurring, and every additional delay in action will result in worsening impacts.
Here are nine key takeaways from the IPCC’s latest landmark climate change assessment:
1. “It is unequivocal that human influence has warmed the atmosphere, ocean and land. Widespread and rapid changes in the atmosphere, ocean, cryosphere and biosphere have occurred.”
Scientists say that their understanding of the world’s climate, and the potential future impacts of climate change, is better than it has ever been. The updated observations and forecasts issued by the IPCC have been made with greater accuracy and certainty.
2. “Human-induced climate change is already affecting many weather and climate extremes in every region across the globe. Evidence of observed changes in extremes such as heatwaves, heavy precipitation, droughts, and tropical cyclones, and, in particular, their attribution to human influence, has strengthened since AR5.”
Scientists say the impacts of climate change are already becoming more evident since the IPCC’s last assessment report, published in 2014. Things are getting more extreme in every part of the world.
3. “Global surface temperature will continue to increase until at least the mid-century under all emissions scenarios considered. Global warming of 1.5°C and 2°C will be exceeded during the 21st century unless deep reductions in CO2 and other greenhouse gas emissions occur in the coming decades.”
Scientists have warned that global temperatures are on track to exceed 2°C of warming this century. Global warming of 1.5°C is expected to be exceeded before 2040 and a draw-down of emissions from the atmosphere will be necessary to keep warming below this level.
4. “Many changes in the climate system become larger in direct relation to increasing global warming. They include increases in the frequency and intensity of hot extremes, marine heatwaves, and heavy precipitation, agricultural and ecological droughts in some regions, and proportion of intense tropical cyclones, as well as reductions in Arctic sea ice, snow cover and permafrost.”
As global warming intensifies, global weather events are predicted to become more extreme. For Australia, this means more frequent and intense droughts, flooding and bushfires. Scientists also predict Australia will see more frequent sand and dust storms.
5. “Many changes due to past and future greenhouse gas emissions are irreversible for centuries to millennia, especially changes in the ocean, ice sheets and global sea level.”
Scientists predict that the impacts of global warming will continue to influence the global climate for thousands of years into the future, pushing the climate to levels not seen for thousands of years prior.
Even modest temperature increases will continue to impact the global climate, including ongoing melting of glaciers and the polar ice-caps, leading to significant levels of sea level rise centuries into the future.
6. “From a physical science perspective, limiting human-induced global warming to a specific level requires limiting cumulative CO2 emissions, reaching at least net zero CO2 emissions, along with strong reductions in other greenhouse gas emissions.”
There is only one way to avoid worsening impacts of climate change: rapidly and significantly reducing greenhouse gas emissions. Predictions suggest that to avoid the most extreme outcomes, reaching net-zero emissions won’t be enough, as the world will need to plan to begin drawing down existing greenhouse gas emissions from the atmosphere.
While the world still emits greenhouse gases, the world will continue to warm.
7. “Australian land areas have warmed by around 1.4°C between 1910 and 2020 (very high confidence), and annual temperature changes have emerged above natural variability in all land regions (high confidence).”
Observations show that Australia is warming at a faster than average rate compared to the rest of the world, already reaching an increase of 1.4°C over the last century. Across all parts of Australia, the warming signal is clear, above normal levels of variability and pushing parts of the country to new record high temperatures and projections suggest this is only going to get worse.
8. “Frequency of extreme fire weather days has increased, and the fire season has become longer since 1950 at many locations (medium confidence). The intensity, frequency and duration of fire weather events are projected to increase throughout Australia (high confidence).”
Australia felt the impacts of global warming during a devastating 2019-20 summer, when bushfires destroyed thousands of homes and claimed the lives of dozens of Australians.
The IPCC has warned that such events are predicted to occur more often and with greater severity, as higher global temperatures exacerbate the conditions in which bushfires thrive.
9. “Changes in several climatic impact-drivers (e.g., heatwaves, droughts, floods;) would be more widespread at 2°C compared to 1.5°C global warming and even more widespread and/or pronounced for higher warming levels.”
The message from scientists is clear – every fraction of a degree matters. The higher global temperatures are pushed by increased concentrations of greenhouse gas emissions, the worse the resulting impacts of climate change on human health.