Urban

Urban strategies and approaches.

Taxonomy Machine Name
niacs_strategy_urban
Taxonomy Alias
urban

Regional climate trends and scenarios for the U.S. National Climate Assessment: Climate of the Northeast U.S.

This document is one of series of regional climate descriptions designed to provide input that can be used in the development of the National Climate Assessment (NCA). There are two components of these descriptions. One component is a description of the historical climate conditions in the region. The other component is a description of the climate conditions associated with two future pathways of greenhouse gas emissions based on IPCC emission scenarios.

Damage from strong storms and sea-level rise may increase in Pacific islands by the end of the century.

Submitted by sdhandler on

Sea level in Hawai'i is projected to rise an additional 1-4 feet by 2100, with increases accelerating strongly after mid-century. In the most extreme scenarios, it is possible that sea level may rise by as much as 8 feet by 2100. Sea-level rise and related increases in storm surges pulsing farther inland will result in land loss in low-lying coastal areas and may result in excessive saltwater inundation of coastal forests.

Climate models generally project that El Nino-like conditions will occur more frequently under climate change in the Pacific region.

Submitted by sdhandler on

The El Niño–Southern Oscillation (ENSO) causes year-to-year changes in climate, with impacts to sea level, precipitation, and storm frequency. Climate models suggest a possible doubling of these extreme events in the 21st century, with El Niño-like conditions projected to occur more frequently. After an El Niño, Hawai'i generally experiences drier conditions from January-March. A La Niña often brings wetter conditions from December-February. An El Niño phase is characterized by decreased trade wind activity, which allows warm waters to flow west to east.

During the 21st century, changes in average annual precipitation are projected to be slight, with potential increases in the southern part of the region and decreases possible in the northern Pacific.

Submitted by sdhandler on

By 2100, under a high emissions scenario, rainfall in wet areas is expected to increase (from small increases to more than 30% increases), while rainfall in dry areas is expected to decrease (from small decreases to decreases of up to 60%). Future precipitation patterns are difficult to project for Hawai'i, due to its steep topography and small-scale variations in climate. Overall precipitation has been trending downward in recent decades, with the sharpest downward trends occurring on western Hawai'i island.

By mid-century, temperatures in Hawai'i are expected to rise by 1-3 degrees F. By late century, under a high emissions scenario, temperatures are expected to rise by 4-5 degrees F.

Submitted by sdhandler on

Temperatures in Hawai'i have warmed by 0.76 degrees F over the past 100 years. Periods of warming and cooling have occurred over the past century, with a statistically significant trend toward warmer temperatures. Warming is occurring at both high and low elevations, although higher elevation areas have been warming faster than lower elevations over the past 30 years. Much of the warming can be attributed to higher minimum temperatures.

Changing winter processes may expose Alaska's forests to more stress.

Submitted by sdhandler on

Alaska cedar is declining and experiencing elevated mortality in large areas. Alaska cedar decline has been attributed to earlier snowmelt, which exposes roots to damage from lower temperatures. Projected future warming is expected to cause additional mortality from freezing-induced root damage, because more snow will be delivered as rain and winter snowpacks will be thinner and more variable. Additionally, warmer winters may allow pests and diseases to expand into previously unavailable territory in Alaska.