- French rugby player whistled but 'serene' on return amid ongoing rape case
- Retegui hat-trick fires five-star Atalanta to hammering of Genoa
- Heavyweights Australia, England off to World Cup winning starts
- Visiting UN refugee agency chief decries 'terrible crisis' in Lebanon
- Spinners come to party as England defeat Bangladesh at T20 World Cup
- Search continues for missing in deadly Bosnia floods
- Man City sink Fulham to get title bid back on track
- France's Auradou whistled on Pau return in Perpignan loss amid ongoing rape case
- A 'forgotten' valley in storm-hit North Carolina, desperate for help
- Arsenal hit back in style after Southampton scare
- Hezbollah heir apparent Safieddine out of contact after strikes
- Liverpool stay top of Premier League as Arsenal, Man City win
- In dank Tour of Emilia, Pogacar shines in rainbow jersey
- DR Congo launches mpox vaccination drive, hoping to curb outbreak
- Trump returns to site of failed assassination
- Careless Leverkusen held to Bundesliga draw
- O'Brien's 'superstar' Kyprios posts landmark win on Arc weekend
- Liverpool suffer Alisson injury blow
- Habosi helps Racing beat Vannes before Auradou's playing return
- Thousands march in London in support of Palestinians, 1 year after Oct 7
- Israel readying response to Iran missile attack
- Schutt, Mooney help Australia beat Sri Lanka in Women's T20 World Cup
- Liverpool extend Premier League lead with win at Palace
- Djokovic 'shakes rust off' to make third round of Shanghai Masters
- 'Imperfect' PSG fighting on all fronts - Luis Enrique
- Struggling Pakistan look to thwart adaptable England
- Child 'trampled to death' in asylum seekers' Channel crossing: minister
- Gauff fights back to set up Beijing final against Muchova
- Guardiola claims Premier League won't delay season for Man City
- Israel to mark October 7 attack as Gaza war spreads
- Gauff fights back to reach China Open final
- Recovering Stokes ruled out of first Pakistan Test
- Hezbollah battles troops on border as Israel pounds Lebanon
- Alcaraz, Sinner breeze into third round of Shanghai Masters
- Bagnaia wins Japan MotoGP sprint to cut Martin's lead
- Alcaraz breezes into third round of Shanghai Masters
- Gaza cultural heritage brought to light in Geneva
- 'Bullet for democracy': Trump returns to site of rally shooting
- Italy targets climate activists in 'anti-Gandhi' demo clampdown
- South Korean cult-horror series 'Hellbound' returns at BIFF
- Nepalis fear more floods as climate change melts glaciers
- Honduras arrests environmentalist's alleged murderer
- Padres pitcher Musgrove needs elbow surgery
- Supreme Court lets stand rules to curb mercury, methane emissions
- Boston beat Denver in NBA exhibition season opener, but Jokic says omens are good
- Chagos diaspora angry at lack of input on islands' fate
- Biden says 'not confident' of peaceful US election
- US trade chief defends tariff hikes when paired with investment
- Lukaku stars as Napoli beat Como to hold Serie A top spot
- Ohtani set for MLB playoff debut as Dodgers face Padres
Carbon capture: how does CO2 removal work?
With global temperatures still on the rise, even the most sceptical of scientists agree that carbon dioxide removal (CDR) is crucial to meet the Paris Agreement goal of capping global warming below two degrees Celsius.
A new global assessment published Thursday says limiting global warming at liveable levels will be impossible without massively scaling up CDR.
But even the most ardent promoters of carbon removal technology insist that slashing emissions remains the primary objective, even if the continued failure to do so has pushed CDR sharply higher on the climate agenda.
Methods range from conventional techniques like restoring or expanding CO2-absorbing forests and wetlands, to more novel technologies such as direct air capture.
Here AFP explains the essentials on CO2 removal:
- What is CO2 removal? -
There are basically two ways to extract CO2 from thin air.
One is to boost nature's capacity to absorb and stockpile carbon. Healing degraded forests, restoring mangroves, industrial-scale tree planting, boosting carbon uptake in rocks or the ocean -- all fall under the hotly debated category of "nature-based solutions".
The second way -- called direct air capture -- uses chemical processes to strip out CO2, then recycles it for industrial use or locks it away in porous rock formations, unused coal beds or saline aquifers.
A variation known as bioenergy with carbon capture and storage, or BECCS, combines elements from both approaches.
Wood pellets or other biomass is converted into biofuels or burned to drive turbines that generate electricity. The CO2 emitted is roughly cancelled out by the CO2 absorbed during plant growth.
But when carbon dioxide in the power plant's exhaust is syphoned off and stored underground, the process becomes a net-negative technology.
- Do we really need it? -
Yes, for a couple of reasons.
Even if the world begins drawing down carbon pollution by three, four or five percent each year -- and that is a significant "if" -- some sectors like cement and steel production, long-haul aviation and agriculture are expected to maintain significant emission levels for decades.
The first-ever State of Carbon Dioxide report concluded that CDR must extract between 450 billion and 1.1 trillion tonnes of CO2 over the remainder of the 21st century -- the equivalent of 10 to 30 times annual CO2 emissions today.
And there is another reason.
The UN's Intergovernmental Panel on Climate Change (IPCC) makes it alarmingly clear that the 1.5C threshold will be breached in the coming decades no matter how aggressively greenhouse gases are drawn down.
CO2 lingers in the atmosphere for centuries, which means that the only way to bring Earth's average surface temperature back under the wire by 2100 is to suck some of it out of the air.
- What's hot, what's not? -
BECCS was pencilled into IPCC climate models more than a decade ago as the theoretically cheapest form of negative emissions, but has barely developed since.
A peer-reviewed proposal in 2019 to draw down excess CO2 by planting a trillion trees sparked huge excitement in the media and among gas and oil companies that have made afforestation offsets a central to their efforts to align with Paris treaty goals.
But the idea was sharply criticised by experts, who pointed out that it would require converting twice the area of India into mono-culture tree farms.
"I don't see a BECCS boom," said Oliver Geden, a senior fellow at the German Institute for International and Security Affairs and an expert on CDR.
Also, planting trees to soak up CO2 is fine -- until the forests burn down in climate-enhanced wildfires.
Among all the carbon dioxide removal methods, direct air capture is among the least developed but the most talked about.
- How fast can we scale up? -
Direct air capture (DAC) is a large-scale industrial process that requires huge amounts of energy to run.
Existing technology is also a long way from making a dent in the problem.
The amount, for example, of CO2 potentially extracted from what will be the world's largest direct air capture plant (36,000 tonnes) -- being built in Iceland by Swiss company Climeworks -- is equivalent to 30 seconds' worth of current global emissions (about 40 billion tonnes).
But the trajectory of earlier technologies such as solar panels suggests that scaling the industry up to remove billions of tonnes per year is not out of reach.
"It's at the upper end of what we've seen before," University of Wisconsin–Madison professor Gregory Nemet. "It's a huge challenge, but it's not unprecedented."
Climeworks announced last week the world's first certified CO2 removal and storage on behalf of paying clients, including Microsoft and software service company Stripe.
M.A.Vaz--PC