Anupam Nath / Associated Press
By JUSTIN GILLIS
June 18, 2015
The
new papal encyclical on the environment is a ringing call to action, a
critique of consumerism and a prophetic warning about the dangers of
ignoring what Pope Francis calls “the ecological crisis.”
But amid all his soaring rhetoric, did the pope get the science right?
The
short answer from climate and environmental scientists is that he did,
at least to the degree possible in a religious document meant for a
broad audience. If anything, they say, he may have bent over backward to
offer a cautious interpretation of the scientific facts.
For example, a substantial body of published science says human emissions have caused all the global warming
that has occurred over the past century. Yet in his letter, Francis
does not go quite that far, citing volcanoes, the sun and other factors
that can influence the climate before he concludes that “most global warming in recent decades is due to the great concentration of greenhouse gases” released mainly by human activity.
Michael
E. Mann, a climate scientist at Pennsylvania State University, pointed
out that the bulk of the evidence suggests that solar changes and
volcanoes have slightly counteracted the warming effect of greenhouse
gases.
“Human
activity is most likely responsible not just for ‘most global warming’
but all of it, and then some, because natural factors have been acting
slightly in the other direction,” Dr. Mann said.
When
reciting facts, as opposed to making judgments, the pope aligns himself
squarely with mainstream scientific thinking. Indeed, those sections of
the document could serve as a syllabus for Environmental Science 101 in
just about any college classroom.
The pope offers
elementary descriptions of a litany of ecological problems, global
warming chief among them, that include air and water pollution, the
wanton destruction of forests, the wasteful use of resources and many
more.
When the pope transitions in his encyclical from fact to judgment, though, his language is less measured.
“The
earth, our home, is beginning to look more and more like an immense
pile of filth,” Francis declares. “In many parts of the planet, the
elderly lament that once beautiful landscapes are now covered with
rubbish.”
The pope is careful to acknowledge
that there has been some progress, with stricter environmental laws in
some countries leading to cleaner air and water.
But
he points out, and environmental experts agree, that impoverished
people bear a disproportionate burden from pollution in rich and poor
countries alike. They have benefited least from fossil fuels, he adds,
but are first in line to suffer as the effects of global warming
intensify.
The pope’s careful calibration of the scientific facts was no accident, of course.
The Vatican
has been consulting for many months with leading experts. Among them
was Hans Joachim Schellnhuber, who is the founder and head of the
Potsdam Institute for Climate Impact Research and a primary
environmental adviser to Chancellor Angela Merkel of Germany.
In
an interview, Dr. Schellnhuber, who was raised a Lutheran, said he was
especially impressed with the pope’s determination to reach beyond the
Catholic faithful, attempting to speak, in Francis’ own words, to “every
person living on this planet.”
The
hard lesson scientists have learned in recent years, Dr. Schellnhuber
said, is that presenting the facts and data about global warming and
other environmental problems has not been enough to move the public to
action. The issues have become so serious that only a broad moral
awakening can offer hope of solving them, he said.
In
aligning himself with mainstream scientific thinking, Francis invites
criticism from people who dispute the science of climate change —
indeed, these contrarians were attacking his paper even before it was
issued.
But the more meaningful critiques in
coming weeks may come from those experts schooled in environmental
policy. The scattered policy prescriptions in the document do not
display the meticulous framing of the scientific statements.
For
instance, Francis devoted a long paragraph to criticizing an approach
called carbon trading that can be used to put a price on greenhouse
emissions, even though many environmental economists favor that
approach.
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