2008-06-20_REVISION - C1980007 - Laserfiche WebLink

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L. INTRODUCTION (CONT.) B. IMPACTS OF CLIMATE CHANGE ON COLORADO, PRESENT AND FUTURE We are already seeing the impacts in Colorado from the global average temperature increase of 1.4 degrees F. Eleven of the past 12 years were the warmest on record worldwide since 1850, when record-keeping began. Glaciers, snowpack and sea ice are shrink- ing, oceans are rising, droughts are longer and more intense in some areas, and weather extremes, such as heavy downpours that cause flooding, intense hurricanes and wildfire, are more frequent. Climate disruption is already happening. While some of the most obvious impacts of climate change won't affect Colorado, the state will ex- perience indirect effects from the displacement of millions of people living in coastal areas, thawing of arctic ecosystems and accelerated loss of usable lands to desert. However, the direct risks to the state are very serious. Observations in recent decades show that Colorado is seeing: • Shorter and warmer winters, with a thinner snowpack and earlier spring runoff. • Less precipitation overall, and more falling as rain than snow. • Longer periods of drought. More wildfires, burning twice as many acres each year than before 1980. • Widespread beetle infestations wiping out pine forests, and die-off in aspen stands. • Rapid spread of West Nile virus due to higher summer temperatures. In the coming decades, scientists project that Colorado and neighboring western states will see: • Temperatures increasing by 3 to 4 degrees F. by 2030. Summer heat extremes will become more frequent and last for longer periods. Air conditioning demand will stress electric utilities, vulnerable populations will suffer increasingly from heat-related illnesses, and summertime air pollution levels will increase. • Longer and more intense wildfire seasons. Fires are projected to claim more land each year than the year before. • Midwinter thawing and much earlier melting of snowpack. The seasonal changes will cause flooding, shorten the ski season by three to six weeks, and place added stress on reservoirs. • Much lower flows in rivers in the summer months and a greater vulnerability to drought. Already over-used river systems will have an even harder time filling existing water rights and future growth. Hydropower production may decline. Water quality will suffer as flows are depleted. • Water shortages and heat stress for irrigated agriculture. Soil moisture will decline, crops will need more irrigation and some crops may not survive mid-summer droughts and heat spells. • Slower recharge in groundwater aquifers. Water storage in the Ogallala aquifer, which underlies eastern Colorado, is projected to decline by 20 percent if temperatures increase by more than 5 degrees F. • Movement of plant and animal species to higher elevations and latitudes. High-elevation habitat will become fragmented. Many of today's high- elevation species will face localized or total extinction. Local ecosystems will be more like those now found at lower elevations. • Insect attacks in forests. Warmer winter temperatures reduce winterkill of beetles, warmer summer temperatures allow faster insect life cycles, and summer droughts further tip the advantage, making forests more vulnerable. Gypsy moths may invade aspen groves. • Less snow cover and more winter rain on farm lands. Pelting rain on bare ground will increase soil erosion. • More weeds. Higher CO2 levels give weeds an advantage over preferred species. 7