Plans to stabilize Earth’s climate depend on new carbon removal technologies – we need to get moving, researchers say

Carbon emissions from fossil fuels continue to rise globally, and 2024 is likely to be the world’s hottest year.

It is becoming increasingly clear that limiting global warming to 1.5°C will require much more than existing efforts to reduce emissions and decarbonize industry. We also need to remove massive amounts of carbon dioxide from the atmosphere, between 7 and 9 billion tons per year.

The Intergovernmental Panel on Climate Change (IPCC) says carbon removal technologies will be needed to meet global and national net zero targets. In other words, net zero would not exist without CO₂ removal because greenhouse gas emissions are not falling fast enough.

CO₂ removal is costly and often consumes energy, water and land, so there are trade-offs. However, the Earth is heading towards climate catastrophe, with global warming of more than 3 degrees Celsius under current global policies. We must do everything we can to avoid disaster. This means reducing emissions wherever possible and removing what’s left.

Within the international scientific community, the debate about carbon dioxide removal is shifting toward a “can-or-should-you?” debate. To “we must”, we recognize the urgency of the situation. It is therefore worth understanding the basics of carbon removal technologies, both old and new, and the role they can play in Australia’s net-zero future.

Why do we need to remove carbon dioxide?

Removing carbon dioxide facilitates natural processes such as storing carbon in trees, rocks, soil, and oceans. This is different from carbon capture and storage, which attempts to remove carbon before it enters the atmosphere.

As Australia’s Climate Change Agency has stated, achieving the national target of net-zero emissions by 2050 will not mean that all emissions will be reduced to zero across the economy. Current plans could leave emissions equivalent to around 25% of Australia’s 2005 emissions that will need to be addressed.

So, how much carbon dioxide is there? Officials say that by the middle of this century, there will be about 133 million tons per year. This equates to billions of additional tons of carbon dioxide being removed over the next 25 years.

How to remove and store carbon dioxide from the atmosphere is one of the federal government’s national scientific research priorities. So let’s take a look at the technology we use today and what we will need in the future.

What technology do you need?

The international scientific community divides carbon dioxide removal technologies into “conventional” (nature-based) and “novel” (new) approaches.

Traditional techniques rely on biological processes such as planting trees, increasing soil carbon levels, and increasing carbon stocks in coastal ecosystems such as mangroves. Carbon is typically stored for short periods of time, from 10 to 100 years.

Unfortunately, many of these natural carbon stores or “sinks” are already becoming saturated. They will also become increasingly vulnerable in a changing climate. For example, forest fires release billions of tons of carbon dioxide into the atmosphere each year.

To reach net-zero emissions, the world needs to find more durable ways to remove CO₂ from the atmosphere at scale. This is where new technology comes into play.

Examples include adding crushed carbonate or silicate rocks to oceans or agricultural land. Research shows that waste rock from mining could be used for this purpose.

Worryingly, new approaches currently account for less than 0.1% of total global carbon removal.

Avoiding potential pitfalls

As with all technologies, carbon removal involves potential risks and trade-offs.

In a market set to be worth as much as US$1.1 trillion (A$1.7 trillion) by 2050, there is always the risk of overestimating returns.

To combat this, the IPCC is developing evidence-based methods to verify carbon removals and ensure their inclusion in national accounts. This promotes transparency and reduces the risk of greenwashing and misleading claims.

Carbon dioxide removal can also impact the environment. For example, some approaches, such as afforestation, can conflict with agriculture and water and land biodiversity conservation. This challenge is further exacerbated by climate change.

Other approaches, such as direct air capture and storage, currently face technical challenges in extracting CO₂ from air without consuming large amounts of energy.

The interests and rights of Australia’s indigenous communities must also be considered. A global survey of indigenous peoples from 30 countries around the world, including Australia, revealed positive attitudes towards climate change intervention technologies. However, this is just a starting point. Greater national commitment is needed on specific carbon removal approaches.

Further research is needed to understand these challenges, including how they are managed and their impact on Australian communities.

A new industry in Australia?

Australia’s vast landmass and vast oceans mean its physical capacity to store carbon is far greater than other countries.

Australia also has access to renewable energy used to power technologies and a skilled workforce to develop and run them.

As with solar and wind energy, tackling carbon removal at the scale needed in Australia will require new industries with their own infrastructure, institutions and processes.

CSIRO and other organizations are making advances in technology, but more needs to be done. Australia needs a national dialogue and a clear vision to deliver carbon removal in a responsible and sustainable way.

Of course, prevention is better than cure. It is better to reduce emissions and stop carbon dioxide from entering the atmosphere in the first place, rather than trying to remove it later. But time is running out and carbon dioxide levels are already too high and need to reach net zero by 2050.

Carbon removal is now essential, along with significant and urgent emissions reductions. To protect our planet for future generations, we must begin permanent carbon removal.

This article is republished from The Conversation under a Creative Commons license. Read the original article.