We already have the technology to reach negative emissions by the 2040s, a new report from climate research group Project Drawdown has concluded.

Drawdown is the projected point where the concentration of greenhouse gases in the atmosphere stops going up, and begins to reduce.

To achieve drawdown, we need to be producing a net-negative amount of greenhouse gases, meaning we have to be removing CO2 and other greenhouse gases from the atmosphere.

The report, based on an extensive review of the scientific literature, identified around 80 areas where we can reduce and reverse emissions.

When grouped by sector, potential emissions reductions by area were ranked as follows:

Energy – especially onshore wind turbines and utility-scale solar
Food waste, agriculture, land rehabilitation – cutting food waste, reducing red meat intake, rehabilitating peatlands, protecting soil carbon, regenerating forests, shifting agricultural practices, restoring degraded ecosystems
Industry – managing refrigerants, switching to alternative refrigerants, switching to alternative cements, reducing, recycling, bioplastics
Building efficiency – insulation, clean cookstoves, solar heating
Transport – improved public transport, electric vehicles, clean shipping, rail.


Waiting for new technology to save us from climate change is a dangerous approach, according to report co-author Jonathan Foley.

He said that their report shows we already have the means to combat climate change, but acknowledges that it will take an enormous and united political and social will to achieve drawdown this century.

"To get to climate safety – to avoid really catastrophic climate change in future – we have an expression 'now, not new'," Dr Foley said.

"We found that when we add together the 80-plus solutions to climate change, and these already exist, we have enough to get drawdown by between the 2040s and the 2060s depending on how decisively we act.

"It will require all of us as ordinary citizens and voters, to politicians, to business and not-for-profit organisations to do our bit."


Food waste is an opportunity

Around a third of all food produced globally is wasted, according to the Food and Agriculture Organisation of the United Nations.

That is equal to around 1.6 billion tonnes, and about $1.6 trillion worth of food, a Boston Consulting Group (BCG) report states.

This is expected to rise to around 2.1 billion tonnes (66 tonnes per second) by 2030.

All that wasted food is wasted energy, said Bernadette McCabe from the University of Southern Queensland's Centre for Agricultural Engineering.

In some countries such as the UK, food waste is collected through kerb-side rubbish and other programs, and broken down anaerobically to produce methane.

That methane is then captured and used as fuel to power things like buses, or in places like California in the US it is fed back into the power grid.

The by-product of the food waste is also re-used as a fertiliser, Professor McCabe said.

"It has the potential to be carbon negative," she said.

"You're displacing fossil fuels like diesel by replacing diesel in buses with methane. And you can capture carbon dioxide, which can be used in greenhouses."

Australia is doing quite well on some fronts, including capturing soil carbon, Professor McCabe added.

However, there needs to be greater investment in infrastructure to convert food waste to energy.

Project Drawdown report says we’ve already got the tech to reach negative emissions by 2040s_1
Burning fossil fuels is increasing the overall CO2 budget in the atmosphere. Photo: ABC News
Women’s role in reducing emissions

The report also identified education and empowerment of women as key to emissions reduction.

In what is referred to as a co-benefit, the authors state that giving women greater agency, education and access to better healthcare leads to falling rates of reproduction.

They estimate that providing access to education and self-determination to all women across the world could have as big an impact as the whole planet switching to plant-rich diets.

But they stress that population is less important than consumption.

"It's critical to note the vast disparities in emissions between … the wealthiest individuals and those of less financial means," the report states.

"Almost half of consumption-related emissions are generated by just 10 per cent of people globally."


Last summer ‘will be absolutely nothing’

The Intergovernmental Panel on Climate Change (IPCC) has predicted that global annual emissions will continue rising beyond 2030, even if all Paris Agreement targets are met.

Project Drawdown report says we’ve already got the tech to reach negative emissions by 2040s_2
Atmospheric CO2 concentrations are expected to rise well into the future. Graph: NOAA

Getting to net-zero emissions by 2050 at the absolute latest is essential if the world is to avoid catastrophic climate change, climate scientist Will Steffen from ANU said.

"If you want to keep [warming] well below 2 degrees Celsius then you really need to hit net-zero by 2040, [but] we're not even close to achieving that," Professor Steffen said.

"We're on target for 3 or 4 degrees. There are some people who say at that temperature the Earth can't even handle human habitation."

But while it is theoretically possible to get emissions into the negatives, he cautioned against conflating fossil carbon with organic carbon.

"The CO2 that we release when we burn fossil fuels has been stored in the earth for hundreds of millions of years," Professor Steffen said.

On the contrary, CO2 that is absorbed by organic sources like trees is only stored for tens to hundreds of years before it is recycled back into the atmosphere.

By burning fossil fuels, we're adding to the overall carbon budget of the atmosphere, Professor Steffen said.

"As long as we continue to use fossil fuels they cannot be offset by growing trees," he said.

–ABC