Science - USA (2022-02-04)

science.org SCIENCE

PHOTO: VASILY FEDOSENKO/REUTERS

By Felix Vogel

T

he latest emissions gap report from

the United Nations Environment

Programme highlighted that current

and planned mitigation measures are

insufficient to achieve the goal of the

Paris Agreement of limiting global

warming to 1.5°C above preindustrial tem-

peratures ( 1 ). When national representatives

gathered at the 26th UN Climate Change

Conference of the Parties (COP26) in Glasgow

last November, a plan to rapidly decrease

methane emissions emerged, with over 100

countries joining the Global Methane Pledge

aimed at reducing global methane emissions

by at least 30% from 2020 amounts by 2030.

While policy-makers try to enact climate-

related legislation, scientists are trying to

identify more cost-effective or quick ways

to curb greenhouse gas emissions. On page

557 of this issue, Lauvaux et al. ( 2 ) highlight

how methane emissions can be effectively re-

duced by targeting ultra-emitter sites identi-

fied by the European Space Agency’s satellite-

based TROPOspheric Monitoring Instrument

(TROPOMI) ( 3 ).

Methane is a gas with a strong climate im-

pact but short atmospheric lifetime of about

9 years. Mitigation of methane emissions can

thus lead to faster reductions in atmospheric

concentrations compared to the reduction of

longer-lived greenhouse gases such as carbon

dioxide (CO 2 ). Consequently, research on at-

mospheric methane and the importance of

reducing its emissions for achieving the 1.5°C

goal have been of increasing interest in re-

cent years (4, 5).

As the second most harmful anthropo-

genic greenhouse gas—after CO 2 —methane

has long been the target for emission reduc-

tion in many countries. However, despite

these efforts, over 350 million tonnes of an-

thropogenic methane are still being emitted

globally every year, with roughly one-third

coming from the fossil fuel industry ( 6 ). In

contrast to CO 2 , which is produced when

the fossil fuel is 100% burned, methane

emissions are often the product of waste,

such as from leaks or the incomplete com-

bustion of fossil fuel, or as the unwanted by-

product from agricultural activities. Those

who favor methane regulations may argue

that, unlike rules governing CO 2 emissions,

methane regulations may incentivize more-

efficient use of resources rather than caus-

ing a feared decrease in productivity—for

example, by reducing methane losses in the

oil and gas sector through leaks and unnec-

essary releases.

For methane emission, past data have

indicated that a small number of super-

emitters are responsible for a dispropor-

tionately large share of the emissions. These

superemitters include thousands of oil and

gas wells in Canada ( 7 ) and the natural gas

distribution infrastructure in US cities ( 8 ).

One study that monitored methane emis-

POLLUTION

Chasing after methane’s ultra-emitters

Leaks from oil and gas companies contribute substantially to global warming

Climate Research Division, Environment and Climate

Change Canada, Toronto, ON, Canada.

Email: [email protected]

PERSPECTIVES

INSIGHTS

490 4 FEBRUARY 2022 • VOL 375 ISSUE 6580