Over the past 100 years, the changing global climate
has shrunk the glaciers on Mt. Hood by more than
one-third. But melting ice on Portlandís mountain
icon is just the most visible of the impacts of
global warming. The changing climate will impact
Portland's future broadly and deeply. It means dramatic
changes here in Portland and the foundations of
the Northwest: our forests, rivers, fish, farms
Since 1900 the Pacific Northwest has warmed by
1.5° F. In the next century, the warming is
expected to accelerate and increase by about 1°
F every 10 years (University of Washington Climate
Impacts Group - http://www.cses.washington.edu/cig/).
The last time this region's climate changed so dramatically
was the Ice Age, when glacial ice sheets covered
much of the Northwest. This time, fueled by vast
quantities of human-caused carbon pollution, the
climate is changing much faster.
Scientists expect that the Northwest will experience
more warming in summer than in winter, and nights
will cool off less than they do today. In addition,
increased urbanization, population growth and related
roads and rooftops will exacerbate the urban heat
island, increasing temperatures even more.
Changes in the water cycle are equally important,
with winters expected to be wetter and summers drier.
This, coupled with higher temperatures, may mean
higher streamflows in the spring, when water is
already abundant, and lower flows in the summer,
when surface water flows are badly needed for irrigation,
drinking water, hydropower and salmon. The trend
will be toward increased use and reliance on groundwater
Forests, a cornerstone of Portlandís economy and
environment, are particularly vulnerable to climate
change. The greatest threats to forest health include
drought, fire, pests, and disease, and climate change
is expected to increase all of these. Oregonís beaches,
too, are threatened by rising sea levels and stronger
storms, and coastal flooding and erosion will increase.
Portland will also experience significant changes
as a result of the response to global warming. Fortunately,
many of the local solutions to climate change offer
substantial community benefits and can provide jobs
as well as improve personal health. Reducing use
of the fossil fuels that cause climate change Ė
primarily gasoline, diesel, natural gas and electricity
from coal and natural gas Ė also reduces the economic
drain of paying for these fuels and improves the
bottom line for businesses and for household budgets.
Renewable energy resources like wind and solar power
offer tremendous economic development potential,
and strategies like adding insulation and upgrading
windows simply make good economic sense. On the
transportation front, increasing walking, bicycling
and transit use has the added benefit of improving
personal health and air quality, while keeping dollars
in the local economy.
Climate change presents enormous challenges, both
globally and here in Portland. However, Portland
is an innovator in developing solutions and was
the first city in the United States to adopt a climate-protection
plan almost 15 years ago. As the world mobilizes
to respond to climate change, Portland is positioned
to lead the way in minimizing carbon emissions,
reducing the disruptions caused by global climate
change and making our community healthier, stronger
and more vibrant.
Mt. Hood August 1984 (top)
and late summer 2003 (bottom). Photos ©Gary
Braasch From his book: Earth Under Fire; How Global
Warming is Changing the World (University of California
Press, September 2007).
Here to view a chart depicting 400,000
years of atmospheric carbon dioxide concentration
and temperature change.
Here to view a chart depicting the
greenhouse gas emissions trend since 1990.