The Intergovernmental Panel on Climate Change (IPCC) has just released the third instalment of its Sixth Assessment Report (AR6). This report focuses on mitigation, aka the “hows and whats” of actually reducing our emissions.
The report, with contributions from 278 authors across 65 countries, presents a vision of the climate future which is at once frightening but also hopeful.
That’s because while our contributions to climate change over the near-decade since the IPCC’s fifth report (AR5) have only increased, our opportunities for mitigating our emissions have become more viable than they were in 2013-14, when AR5 was released.
Pollution since 2010
The sixth report shows that global emissions have increased dramatically.
“From 2010 onwards we had the highest increase in greenhouse gas emissions in human history,” says Tommy Wiedmann, a professor of sustainability research at UNSW and adjunct science leader at CSIRO. “Reaching 59 gigatonnes of CO2 equivalents in 2019.”
While there was a drop of about 6% in global emissions in 2020 thanks to the effective slowing of transport by COVID-19, emissions in 2021 rose again to match 2019’s record-breaking output.
Wiedmann, who is a lead author on chapter 2 of the report, says that some activities that produce greenhouse gases intensively have grown particularly fast since 2010. These include the aviation sector, which was contributing 29% more emissions in 2020 than in 2010, as well as energy demand for the cooling of residential buildings, which rose by 40%, and the sale of SUVs (sports utility vehicles), which rose by 17%.
Perhaps most sobering, the report found that emissions from existing and planned fossil fuel infrastructure alone are higher than the total emissions that would be consistent with limiting warming to 1.5 degrees Celsius.
1.5 and 2 degrees Celsius: what’s the deal?
Human activities are estimated to have caused approximately 1°C of global warming since before the industrial revolution, and this number is likely to reach 1.5°C between 2030 and 2050 if we don’t curb our behaviours now.
1.5°C of warming has been identified by climate scientists as a critical threshold beyond which the impacts of climate change on human life and Earth’s ecosystems become far more severe.
Limiting global warming to 1.5°C requires us to curb our emissions by about 45%-50% by 2030, and to reach net-zero emissions by 2050, as set out in the Paris Agreement.
2°C of warming is seen as a more reasonable backstop – another threshold beyond which the consequences become even more frightening. Limiting warming to 2°C will require us to reach net zero by the early 2070s.
The good(ish) news: mitigation pathways are cheaper and easier than before
If those numbers have left you dizzy and deflated, you wouldn’t be alone. But there’s a glimmer of hope, because the strategies we know we need to adopt if we’re going to have any hope of reducing our emissions are now cheaper, more technologically advanced, and more accessible than ever.
“Since 2010, the cost of renewable energy technology has fallen dramatically,” notes Wiedmann. “Solar power is now 87% cheaper, wind 55%, and batteries are 85% cheaper than 10 years ago.”
Because of this, the authors of the sixth IPCC report are confident that greenhouse gas emissions could be halved by 2030, provided renewable energy rapidly replaces fossil fuels – and that’s a big caveat, because the fossil fuel sector stubbornly churns on.
Nonetheless, Peter Newman, a professor of sustainability at Curtin University and co-ordinating lead author on chapter 10 of the report which covers the transport sector, says the gains in renewable technology in the past decade have even stunned the experts.
“We did not predict that in the early days, 10 years ago,” he says.
Liam Wagner, associate professor of energy economics at the University of Adelaide, says the decline in renewable energy costs is thanks to massive advancements in technology over the past decade: “We’ve seen a rapid decrease in price simply because we’ve learned by doing.”
The fall in battery costs means electric vehicles could become more accessible, and soon. That’s important, because the perceived high cost of electric vehicles is considered a significant barrier to their uptake in Australia, and because road transport accounts for about 16% of Australia’s total emissions.
Despite this, experts are unanimous that we’re not electrifying our energy networks nearly fast enough, either globally or here in Australia.
“We’ve had an inconsistent and ineffectual energy policy in Australia for the last 10 years,” says Wagner. As for fossil fuels, “they are the boat anchor that’s been dragging us on a much slower pace than we could have achieved.”
“The change is not coming fast enough,” agrees Wiedmann. “The report also confirms that all the gains we’ve made in energy efficiency in the last decade have been more than outpaced by economic growth and population growth.”
Moving away from this intractable situation would require considerable new policy commitments, says Wagner.
“I would really like to see the redesign of the national electricity market to better cope with the integration of renewables and also to expedite the retirement and closure of coal-fired power stations,” he says. “And I would like to see a significant push towards electric vehicles for personal transport.”
According to Iain MacGill, an expert in renewable power and energy systems engineering at UNSW Sydney, building our renewable capacity to keep pace with emissions commitments would be a serious challenge.
“The IEA (International Energy Agency) Net Zero Emissions 2050 scenario suggests that we need wind and solar to sustain the same compounding growth rate they have achieved over the past decade, 20% annually, every year to 2030,” says MacGill. “Of course, with compound growth, the actual capacity of wind and solar that has to be deployed each year has to increase by 20%, doubling installed capacity every three to four years.
“This will be an extraordinary challenge. If other clean energy options including bioenergy, carbon capture and storage and nuclear don’t grow as fast as the IEA projects in its net-zero scenario, the task for renewables will be even greater.”
As the IPCC’s sixth assessment cycle wraps up this year, Australia is reckoning with extreme weather patterns predicted to worsen as the climate warms. Meanwhile, the Great Barrier Reef is facing its fourth mass bleaching event since 2016 and the sixth ever recorded. Australia and the world face an uncertain future.
So, is there cause for hope, amid a dire set of predictions? As one of the authors on a report eight years in the making, Wiedmann is cautiously optimistic.
“I think there is very good news [in the report],” he says. “But the good news is really that the options are available and they are at hand, we really just need to go for them.”
Newman, for his part, is reflective: “It’s worth remembering that the IPCC is largely a voluntary organisation; these people have worked day and night over years of extensive commitment,” he says. “And it is a labour of love.
“It’s accelerating the opportunities that are presented to us, and we can accelerate our hope for the future. It’s very hard to see how that would have ever happened without the IPCC.”
Frank Jotzo, director of the centre for climate economics and policy at the Australian National University (ANU) and a lead author on chapter 13 of the report, is succinct: “The opportunities are there, the time to act is now.”
Amalyah Hart has a BA (Hons) in Archaeology and Anthropology from the University of Oxford and an MA in Journalism from the University of Melbourne.
Read science facts, not fiction...
There’s never been a more important time to explain the facts, cherish evidence-based knowledge and to showcase the latest scientific, technological and engineering breakthroughs. Cosmos is published by The Royal Institution of Australia, a charity dedicated to connecting people with the world of science. Financial contributions, however big or small, help us provide access to trusted science information at a time when the world needs it most. Please support us by making a donation or purchasing a subscription today.