PROVIDENCE, R.I. — By 2035, the Northeast is expected to be more than 3.6 degrees warmer on average than during the pre-industrial era, the largest increase in temperature in the contiguous United States, according to the newest installment of the National Climate Assessment released on Friday.

The region — the most densely populated in the nation — will hit that warming milestone more than two decades before global average temperatures reach the same level, according to the comprehensive new report, citing research first published last year by climate scientists at the University of Massachusetts at Amherst.

Coupled with some of the highest rates of ocean warming and sea level rise in the nation, the Northeast is already experiencing changes to the environment and ecosystems that are increasing risks to its people, infrastructure and economy, the report says.

The risks tied to climate change include inland flooding from more intense rain events, surges from more severe coastal storms, temperature extremes and episodes of poor air quality.

"The changing climate of the Northeast threatens the health and well-being of residents through environmental changes that lead to health-related impacts and costs, including additional deaths, emergency-room visits and hospitalizations, higher risk of infectious diseases, lower quality of life, and increased costs associated with health-care utilization," the report says.

The authors of the report — which include scientists from NASA, the U.S. Environmental Protection Agency and the Department of Energy — found that Northeast's cities are also more vulnerable to climate threats because of higher concentrations of historic structures, as well as older housing and infrastructure, as compared with other regions.

The recent temperature changes in the region have been felt most acutely in winters, which have warmed three times faster than summers, and are expected to become milder still, with fewer cold extremes and frost days.

The Northeast is also the most heavily forested region in the nation, and the changes in seasonal temperatures are causing trees and plants to leaf out and bloom earlier, affecting interactions with animal species. Warmer winters are also contributing to the range expansion of insect pests, such as the emerald ash borer and the southern pine beetle, which have both been found in Rhode Island for the first time in recent years.

Oceans, too, are warming, pushing fish and shellfish species historically associated with the region north and further offshore to deeper waters in search of lower temperatures. Numbers of important species, such as cod, scallops and lobster, are expected to decline in the Northeast.

The report applauds officials in the Northeast for taking steps toward planning for climate change, mentioning by name the sea-level rise and storm surge mapping program called STORMTOOLS developed by the University of Rhode Island and the Rhode Island Coastal Resources Management Council.

But those efforts to prepare for adaptation and protection won’t go far enough.

“Although timely adaptation to climate-related impacts would help reduce threats to people’s health, safety, economic well-being, and ways of life, changes to those societal elements will not be avoided completely,” the report says.

— akuffner@providencejournal.com / (401) 277-7457