The world climate is changing more rapidly than predicted, resulting in accelerating sea level rise, droughts, floods, storms and heat waves. These will impact some of the world's poorest and most vulnerable people, disrupting food production, and threatening important species, habitats and ecosystems.
Depending on the level of worldwide greenhouse gas emissions, the world faces between 2 and 11ºF of warming over the next century.
Impacts to Juneau
Over the past 60 years, Juneau has already experienced about 3ºF increase in average winter temperatures, with a decrease in annual snowfall at sea level from approximately 109 inches to 93 inches.
The projected impacts of climate change projections for Juneau include:
- Average air temperatures in Juneau will increase by approximately 10°F by the end of the current century.
- By the end of the 21st century, shrubs and trees will have colonized elevations currently characterized as alpine or tundra habitat in southeastern Alaska.
- Many ecological responses to climate change will not be predictable and some may be counterintuitive. For example, yellow cedar trees are freezing in spring as temperature warms due to a loss of insulating snow cover.
- Increasing temperature and precipitation likely will alter the ecology of salmon in southeastern Alaska. Early entry into the marine environment - when food resources are low or absent - will decrease growth and survival.
- Increased intensity and frequency of coastal storms will negatively impact shoreline and wetland nursery areas for many marine species.
- Changes in climate may out pace the capacity of some plants and animals to adapt, resulting in local or global extinctions.
- Rapid changes in the ecology of terrestrial and marine environments will alter commercial, subsistence, and recreational harvesting in ways that cannot be readily predicted.
- While large regions of Alaska are expected to suffer damage to infrastructure associated with rises in sea level, coastal erosion, melting of permafrost, and reductions in sea ice, those impacts will be minimal for the CBJ.
- Reductions in winter snow cover at lower elevations will negatively impact winter recreational activities in the CBJ.
- Limiting the impacts of greenhouse gas emissions will require reductions in the consumption of fossil fuels. Those reductions will negatively impact transportation to and within the CBJ.
- Economic costs of community responses to climate change are likely to increase over time, and proactive responses will minimize negative impacts.
- Salmon and other marine resources that are important to Southeast Alaska may be affected by ocean acidification, and by increasing temperatures and precipitation, probably decreasing growth and survival.
(primary source: Climate Change: Predicted Impacts On Juneau April 2007)