BBC Science Focus - 03.2020

20 IDEAS FE ATURE

PESTS DRIVEN OFF

WITHOUT CRUELTY

Labs investigate gene

drives to fend off invasive

species like grey squirrels

and cane toads

Another potential use for gene-editing is wiping out

pests. Dubbed “gene drives”, self-replicating edits based

on CRISPR technology could ravage through entire

populations. In lab trials, the newly-introduced DNA often

makes one sex sterile, duplicating itself to infect both

copies of an animal’s chromosomes so that it’s passed

on to all its offspring. Some mosquitoes have developed

resistance against gene drive mutations, but researchers

believe they’ll be able to pull off the technique as long

as they target the right genes. For safety, scientists are

designing ‘override’ drives capable of reversing the edits.

In a 2018 paper , researchers from Edinburgh’s Roslin

Institute, which created the first cloned sheep (“Dolly”),

suggested gene drives could deal humanely with the

Australian cane toad problem. The toxic toads were

introduced from Hawaii in 1935 and have killed almost

anything that has tried to eat them ever since. The same

scientists propose controlling grey squirrels with gene

drives, in order to save the UK’s native reds.

A rapid shift away from using fossil

fuels is what’s required if we’re going to

keep the average global temperature

rise within the 1.5°C window needed

to mitigate the worst effects of climate

change. But that’s not all we can do.

Instead of trying to limit our carbon

emissions, there is scope to actually

remove them from the atmosphere.

That’s what Microsoft announced it

would start doing, when the software

giant kicked off 2020 by revealing its

intention to be carbon negative by 2030.

But that’s not all; Microsoft also said that

by 2050, it plans to “remove from the

environment all the carbon the company

has emitted since it was founded in 1975.”

Achieving that goal will take more

than simply switching to renewable

energy sources, electrifying its fleet of

vehicles and planting new forests. Hence,

Microsoft is monitoring the development

of negative emissions technologies that

include bioenergy with carbon capture

and storage (BECCS), and direct air

capture (DAC).

BECCS uses trees and crops to

capture carbon as they grow. The

trees and plants are then burnt to

generate electricity but the carbon

emissions are captured and stored

deep underground. DAC uses fans to

draw air through filters that remove

the carbon dioxide, which can then

be stored underground or potentially

even turned into a type of low-carbon

synthetic fuel.

Both methods sound promising

but have yet to reach a point where

they are practical or affordable on a

scale necessary for them to have a

significant impact on climate change.

Microsoft’s hope, as well as those

of everyone else looking to turn the

tide of the climate crisis, is that these

technologies, and others, will develop

further over the years to come to a

point that makes them viable.

4

SILICON VALLEY TRIES TO GO

CARBON NEGATIVE

The tech world is hoping it can turn back the clock

on climate change by removing carbon emissions

5

GETTY IMAGES X2, SAM KRIEGMAN/DOUGLAS BLACKISTON