Climate impacts
A planet that is 4C warmer than present may not sound all that bad, and certainly in regions that may have a limited growing season there could be benefits. Indeed the impacts of climate change will include winners and losers. The list of projected impacts of climate change on the environment and society are many, so we highlight a few here and focus more specifically on impacts for the Pacific Northwest. We consider "impacts" as things that might occur without proper coping measures or adaptation.
A warmer planet will dramatically increase the frequency of extremely warm days and months at the expense of extremely cold days and months. The severe heat waves that have been seen in recent decades such as those across the central US in 2012, Texas in 2011, Russia is 2010, Europe in 2003, will be commonplace in coming decades. Such events will likely be tied to increases in vegetation mortality, agricultural losses, wildfire and potential increased human mortality.
While geographically and seasonally variable, most projections also call for increases in intense precipitation events. Flooding concerns and their direct and indirect impacts on human health, infrastructure and water supplies will be heightened.
A warmer planet will dramatically increase the frequency of extremely warm days and months at the expense of extremely cold days and months. The severe heat waves that have been seen in recent decades such as those across the central US in 2012, Texas in 2011, Russia is 2010, Europe in 2003, will be commonplace in coming decades. Such events will likely be tied to increases in vegetation mortality, agricultural losses, wildfire and potential increased human mortality.
While geographically and seasonally variable, most projections also call for increases in intense precipitation events. Flooding concerns and their direct and indirect impacts on human health, infrastructure and water supplies will be heightened.
Sea level
Sea level has risen around 20cm since 1850, mainly through thermal expansion of the oceans and melting of land ice. Projections feature an acceleration of this change throughout the 21st century with and potential 1-m rise in sea level. While a moot point for uplanders in Idaho. A significant portion of the global population (100 million people) live less than 1-meter above current sea level and may be displaced with rising waters. View an interactive map of how sea-level rise might displace coastal locales across the US. Saline water infiltrating into freshwater supplies is another concern for coastal cities.Note also, that when you combine the influence of sea level rise and storm surge from landfalling storms, the area at risk becomes significantly larger. Warming ocean waters are reasoned to increase the potential intensity of tropical storms. Estimates are that for every 1C increase in ocean surface temperatures, surface winds of tropical storms increase 1-8% and rainfall increases by 6-18%. Projecting where and when tropical storms will form in a changing climate is challenging however.
(1) Ocean acidification. Increasing levels of atmospheric carbon dioxide are partially offset by uptake of carbon by the ocean. However, as the surface ocean takes up carbon, this carbon is converted to carbonic acid that results in a lowering of oceanic pH. Lifeforms in the ocean that are ill-adapted to acidic conditions will suffer, including valued ecosystems such as coral reefs and primary producers including plankton.
(2) Agriculture. A warmer planet with higher levels of carbon dioxide might be beneficial for crops and CO2 is a fertilizer that helps photosynthesis. However, declines in water availability and heat stress may quickly erase any potential gains. The record heat and drought across the central US during 2012 resulted in economic losses of approximately 1% of the US gross domestic product, topping 100 billion US dollars. Similar losses have been seen in recent heat extremes in Europe and Russia agriculture. Some regions however, will clearly see benefits from a warming planet.
Log in to BBLearn and go to Module 8. Click on the Study Area icon, and in the Study Area, under Videos for Chapter 8, select 'Temperature and Agriculture: Science for a Hungry World: Agriculture.'
(3) Ecosystems. The speed of changes in climate exceed observed paces of change by orders of magnitude. Vegetation distributions will likely change as a result, with species that are able to adapt to such changes winning at the expense of the ill-adapted species. Changes in the frequency of vegetation disturbance associated with insect attack, wildfire and vegetation mortality will all be modified under a changing climate and play a role in the shaping of ecosystems. Climate change will likely result in the disappearance of certain ecosystems and species, and the development of novel regions.
An interactive map of projected climate impacts to a warming planet can be found here.
Pacific Northwest Impacts
- Earlier snowmelt and reduced snowpack, reducing levels in some reservoirs
- Increasing competition for scarce water supplies
- Reduced winter activities
- Less groundwater recharge (e.g., Snake River aquifer)
- Increased wildfire potential
- Forests stressed by droughts and high temperature leading to potential increase in areal extent impacted by bark beetle
- Increased coastal erosion and loss due to sea-level rise
- Reduction in hydropower generation during summer.
- Increased stream temperatures and reduced summer flows will reduce habitat suitable for cold-water fisheries.
- Large shifts in vegetation
For more information click here.
Log in to BBLearn and go to Module 8. Click on the Mastering Assignments icon, and in the Study Area and complete "Assignment 8.4: Mapping Climate Impacts."