The Pacific Northwest is already being impacted by climate change, according to the latest National Climate Assessment (NCA). The consequences for the region’s economy and natural resources are significant. Washington, Oregon, and Idaho can expect reduced snowpack for water supplies, coastal inundation and ocean acidification, loss of forestland to fire and disease, and changes to the agricultural landscape. Even so, changes here will be less severe than elsewhere, and the region could expect to see environmental refugees as storms, floods, and fires ravage the rest of the country.

The 2014 NCA is the third version since the U.S. Global Change Research Program was created in 1990. The program is charged with helping the nation and world understand, predict, and respond to human-caused and natural processes of global environmental change. The latest report was authored by over 300 researchers and saw collaboration between 13 federal agencies, including the Departments of Agriculture, Energy, Interior, the EPA, NASA, and the National Science Foundation. It is available in an online interactive format, and the findings are summarized here. The Northwest is already a leader in renewable energy and the adoption of sustainable practices in business and government, so the NCA’s findings are equally applicable to further reducing our carbon footprint and mitigating the inevitable effects of environmental changes.

The northwest has seen increased temperatures, and they will continue to rise. From 1895 the 2011 the annual average increase was 1.3°F. Compared to the 1970 to 1999 period, at the end of the century the projected average annual increase is within the wide range of 3.3°F to 9.7°F and depends on future global emissions. Summer precipitation may decrease by as much as 30 percent by 2100, which will have major impacts on agriculture, water supplies, and wildfires.

2014 set a record for wildfires in Washington state, with over 363,000 acres  burned. California (631,000 acres) and Oregon (957,00 acres) also had a particularly destructive fire seasons due to continuing drought like conditions. The NCA reports that by the 2080s, the median area burned in the northwest region could quadruple to 2 million acres (3,125 square miles) per year. The northward spread of the mountain pine beetle due to warming temperatures also increases the risk of fire as dead trees become fuel.

The northwest depends on a balance of water supplies for consumption, irrigation, and hydroelectricity. The NCA reports that modeling studies predict with near certainty that reductions in summer precipitation will occur in all watersheds with significant snowmelt. Seattle is entirely dependent on the Tolt and Cedar River watersheds for its water supply. Reduced river flows will require additional tradeoffs between reservoir systems, especially as increased temperatures increase electric power demand and water for farming. In the Columbia Basin, by the 2080s a 20 percent reduction in hydropower production may be necessary to ensure adequate water flow for fish.

More than 300 types of crops are grown on northwest farms. Lack of water for irrigation will increase the probability that field crops and tree fruit will face heat stress. For a few decades some crops are expected to benefit from a longer growing season and, ironically, increased carbon dioxide in the atmosphere. For instance, the northwest can be expected to become increasingly friendly to vineyards. Ocean acidification is also already harming marine wildlife and the industries that depend on them, especially the region’s large shellfish harvesters. At least one Washington company has already relocated their oyster farming to Hawaii due to rapid changes along northwest coastlines. Scientists are investigating whether acidification and warming waters are contributing to the huge starfish die-off all along the west coast. The ocean’s increasing absorption of carbon dioxide has the potential to massively disrupt marine ecosystems unlike anything else. The Seattle Times has published a series of articles and videos on the situation.

Globally, sea levels have risen an average of eight inches since 1880. They are expected to rise another 12 to 48 inches by 2100. Regional factors, such as land subsidence, ocean winds and currents, and the gravitational effects of ice sheets, will effect local rise. Increased sea levels will be especially evident during storm surges, when wind pushes water ashore. The Puget Sound’s steep shorelines may actually spare most of the region from rising waters, but preparedness is still advisable. The NCA found that the cost of repairing flood-damaged infrastructure and structures is four to ten times as costly as preventative measures. Such measures might include raising buildings, constructing seawalls or artificial wetlands, sealing conduits and tunnels, and relocating transportation routes. While many officials recognize the threat of sea level rise, the mixture of federal, state, and local regulations have slowed responses.

Cities are particularly sensitive to climate change because of their large and growing populations. Approximately 245 million people live in U.S. cities, and that is expected to grow to 364 million by 2050. Cities are  dependent on aging and fragile infrastructure systems that are interdependent. Many cities are located in coastal areas, and so are particularly sensitive to sea levels and weather. City planners and elected officials have the most direct responsibility to respond to these issues through plans, policies, and budgets.

The NCA emphasizes that local measures, such as building codes, zoning regulations, and hazard mitigation plans, can support adaptation. For the few cities that have taken a serious stance on climate change, getting the public on board has helped to educate the community and identify vulnerable populations while mobilizing people to support policy actions. Last year the three northwest states and British Columbia signed a climate pact that outlines actions to reduce carbon emissions. Creating oversight at the local level, such as a “Puget Sound Panel on Climate Change”, could help to ensure implementation.

Washington’s goal is to reduce carbon emissions to 66.3 metric tons by 2035.  Click to enlarge. (The Seattle Times)

Action at the state level can also more broadly effect change. A 2008 law mandates that Washington reduce its overall emissions to 75 percent of 1990 levels by 2035. Washington state governor Jay Inslee is planning to push for a package of carbon-reduction measures, with the primary tool being either a tax on carbon emissions or a “cap and trade” system similar to California, where industrial polluters can trade rights to emit carbon dioxide. The economic premise behind carbon pricing is that emissions are a failure of the free market and an unaccounted externality that has significant social costs. The biggest potential for reductions, by far, is the transportation sector. But the state’s Republican-controlled Senate will likely blockade any increased burden on the state’s businesses and residents. At the national level, U.S. President Obama recently made an agreement with China to more aggressively pursue environmental policies that are already in place.

Cliff Mass, professor of atmospheric sciences at the University Washington, has colorfully illustrated how water availability, heat waves, storms, and floods will increasingly affect the U.S. to some degree or another. Despite the impacts described earlier, the northwest will be relatively stable compared to the rest of the country. This may make it a climate refuge that will experience at least a slightly higher population growth. Seattle is already the nation’s fastest growing city, so people are moving here for reasons other than the weather. But the issue is worth considering for local planners who rely on official population projections used to plan for residential growth, commercial space, and capital facilities.

Climate-induced migration is nothing new in human history, but the speed and scale of modern environmental refugees may be considerable. Several island nations are planning to relocate their entire populations as shorelines disappear. Remote villages in Alaska are being eaten away by accelerating erosion. Some refugees may temporarily relocate, while others will be permanent. The population of New Orleans, for instance, has still not recovered to its to pre-Hurricane Katrina level.

Planners must tackle climate change from two directions. Enabling efficient land uses and shorter transportation distances are key to reducing carbon emissions, not to mention improving public health and economic outcomes. But decades of change are already locked in, so dealing with the ongoing effects of decreased water supplies, temperature rise, and sea level rise is also necessary through adaptation. Understanding that projections may vary widely and the future is hard to predict, planners can nonetheless employ the best available science when working to prepare their communities for changes to come.