The significant increased wildfire activity in Alaska in recent decades is associated with manmade and natural factors. A Climate Science Special Report estimates the risk of devastating wildfires in the state has likely risen by 33%–50% and is projected to increase fourfold by the end of 21st century. The 2015 fire season in Alaska burned the second-largest number of acres since 1940, when record keeping began.
2. Arctic Ocean: Alaska
The amount of sea ice in the Bering and Chukchi seas that separate Alaska from Asia fell to 135,000 square miles last November, the lowest level for that time of year in 40 years.
3. Arizona: Phoenix
In late June 2017, Phoenix, Arizona — always among the hottest cities in the nation — recorded a high temperature of at least 112 degrees for nine straight days, tying a previous city record set in 1990, according to the National Weather Service.
4. Central Pacific: Near Hawaii
The central Pacific Ocean near Hawaii typically has cooler ocean temperatures and stronger vertical wind shear patterns, conditions not favorable to hurricanes. However, according to CSSR findings, the greater tropical storm activity in 2014 and 2015 was associated with warmer oceans and weaker vertical wind shear that was linked to the effects of El Niño and human-caused climate change.
5. Central United States: Oklahoma
A drier-than-average winter, worsening drought conditions, and strong winds in the spring — some gusting over 40 mph — led to wildfires in April in Oklahoma and the central United States.
Scientists warn that man-caused global warming will likely increase the potential for wildfires. Weather conducive to fires is expected to become both more extreme and span longer times as a result of climate change.