Critical measures of global heating reaching
tipping point, study finds
Carbon emissions, ocean acidification, Amazon clearing
all hurtling toward new records
Vast areas of the Amazon rainforest are being burned
and cleared for grazing cattle — a double blow to global warming, as cattle
produce methane and cleared forests release carbon into the atmosphere.
Katharine
Gammon
Wed 28 Jul
2021 01.00 BST
A new study
tracking the planet’s vital signs has found that many of the key indicators of
the global climate crisis are getting worse and either approaching, or
exceeding, key tipping points as the earth heats up.
Overall,
the study found some 16 out of 31 tracked planetary vital signs, including
greenhouse gas concentrations, ocean heat content and ice mass, set worrying
new records.
“There is
growing evidence we are getting close to or have already gone beyond tipping
points associated with important parts of the Earth system,” said William
Ripple, an ecologist at Oregon State University who co-authored the new
research, in a statement.
“The
updated planetary vital signs we present largely reflect the consequences of
unrelenting business as usual,” said Ripple, adding that “a major lesson from
Covid-19 is that even colossally decreased transportation and consumption are
not nearly enough and that, instead, transformational system changes are
required.”
While the
pandemic shut down economies and shifted the way people think about work,
school and travel, it did little to reduce the overall global carbon emissions.
Fossil fuel use dipped slightly in 2020, but the authors of a report published
in the journal BioScience say that carbon dioxide, methane and nitrous oxide
“have all set new year-to-date records for atmospheric concentrations in both
2020 and 2021”.
In April
2021, carbon dioxide concentration reached 416 parts per million, the highest
monthly global average concentration ever recorded. The five hottest years on
record have all occurred since 2015, and 2020 was the second hottest year in
history.
The study
also found that ruminant livestock, a significant source of planet-warming
gases, now number more than 4 billion, and their total mass is more than that
of all humans and wild animals combined. The rate of forest loss in the
Brazilian Amazon increased in both 2019 and 2020, reaching a 12-year high of
1.11 million hectares deforested in 2020.
Ocean
acidification is near an all-time record, and when combined with warmer ocean
temperatures, it threatens the coral reefs that more than half a billion people
depend on for food, tourism dollars and storm surge protection.
However,
there were a few bright spots in the study, including fossil fuel subsidies
reaching a record low and fossil fuel divestment reaching a record high.
In order to
change the course of the climate emergency, the authors write that profound
alterations need to happen. They say the world needs to develop a global price
for carbon that is linked to a socially just fund to finance climate mitigation
and adaptation policies in the developing world.
The authors
also highlight the need for a phase-out and eventual ban of fossil fuels, and
the development of global strategic climate reserves to protect and restore
natural carbon sinks and biodiversity. Climate education should also be part of
school curricula around the globe, they say.
“Policies
to alleviate the climate crisis or any of the other threatened planetary
boundary transgressions should not be focused on symptom relief but on
addressing their root cause: the overexploitation of the Earth,” the report
says. Only by taking on this core issue, the authors write, will people be able
to “ensure the long-term sustainability of human civilization and give future
generations the opportunity to thrive”.
Sem comentários:
Enviar um comentário