By
HENRY FOUNTAIN and BRAD PLUMER
The
same, only worse.
Global
warming is affecting the United States more than ever, and the impacts — on
communities, regions, infrastructure and sectors of the economy — are expected
to increase.
That’s
the gist of Volume II of the National Climate Assessment, a draft report made
public on Friday that focuses on the current and future impacts of climate
change. The draft will eventually accompany a report on the science of climate
change that was unveiled by 13 federal agencies in its final form on the same
day.
In
addition to comments by members of the public, Volume II is being reviewed by
an expert committee of the National Academies of Sciences, Engineering, and
Medicine. After revisions by the agencies involved it is expected to be
published in December 2018.
Like
the scientific report, the draft of Volume II contains many of the same
findings cited in the previous National Climate Assessment, published in 2014.
But reflecting some of the impacts that have been felt across the country in
the past three years, some of the emphasis has changed.
Here’s
a look at some of what’s new in the draft assessment.
Predicted
impacts have materialized
More
and more of the predicted impacts of global warming are now becoming a reality.
For
instance, the 2014 assessment forecast that coastal cities would see more
flooding in the coming years as sea levels rose. That’s no longer theoretical:
Scientists have now documented a record number of “nuisance flooding” events
during high tides. In 2014, nearly half of residents in Hampton Roads, Va.,
could not get out of their neighborhoods at least once because of tidal
flooding.
Meanwhile,
as the oceans have warmed, disruptions in United States fisheries, long
predicted, are now underway. In 2012, record ocean temperatures caused lobster
catches in Maine to peak a month earlier than usual — and the distribution
chain was unprepared.
A
focus on air quality
While
much of the discussion of climate change looks at the role of carbon dioxide
and other greenhouse gases in warming the planet, the draft report puts a
renewed emphasis on the impacts of other atmospheric pollutants like ozone and
smoke, which can cause respiratory problems and lead to premature death.
The
draft notes with “high confidence” that climate change will increase ozone
levels, as rising temperatures and changes in atmospheric circulation affect
local weather conditions. But the increases will not be uniform; by near the
end of the century the worst ozone levels will be found across a wide expanse
of the Midwest and Northern Great Plains, while levels are expected to improve,
at least somewhat, in parts of the Southeast.
The
report reiterates what residents of the West have learned from hard experience:
that warmer springs, longer dry seasons in the summer and other impacts are
lengthening the fire season. The smoke from fires affects not only health, the
report says, but visibility.
Adaptation,
adaptation, adaptation
Since
2014, more detailed economic research has estimated that climate change could
cause hundreds of billions of dollars in annual damage, as deadly heat waves,
coastal flooding, and an increase in extreme weather take their toll. Unless,
that is, communities take steps to prepare beforehand.
The
previous assessment warned that few states and cities were taking steps to
adapt to the impacts of climate change. That’s slowly changing, the new draft
finds. More and more communities are taking measures such as preserving
wetlands along the coasts to act as buffers against storms.
But
outside of a few places in Louisiana and Alaska, few coastal communities are
rethinking their development patterns in order to avoid the impacts from rising
seas and severe weather that the report says are surely coming.
Beyond
borders
The
United States military has long taken climate change seriously, both for its
potential impacts on troops and infrastructure around the world and for its
potential to cause political instability in other countries.
The
draft report cites these international concerns, but goes far beyond the military.
Climate change is already affecting American companies’ overseas operations and
supply chains, it says, and as these impacts worsen it will take a toll on
trade and the economy.
Global
warming and natural disasters are also affecting development in less affluent
countries. That, the draft says, puts additional burdens on the United States
for humanitarian assistance and disaster aid.
It’s
all tied together
The
draft report suggests a different approach to assessing the effects of climate
change, by considering how various impacts — on food supplies, water and
electricity generation, for example — interact with each other.
“It
is not possible to understand the full extent of climate-related impacts in the
United States without considering these interactions,” the report says.
It gives several
examples, including recent droughts in California and elsewhere that, in
combination with population changes, affects demand for water and energy. The
draft also cites Hurricane Sandy, five years ago, which caused cascading
impacts on interconnected systems in the New York area, some of which had not
been anticipated. Flooding of subway and highway tunnels, for example, made it
more difficult to repair the electrical system, which suffered widespread
damage.