The nine-state area from Pennsylvania to Maine, if considered as its own country, produces enough emissions that it would rank seventh in the world - and a research group of scientists and economists said much can be done locally to curb global warming.

"The emission choices we make today and over the next several decades will largely shape the climate that our children and grandchildren inherit," said Peter Frumhoff, who led the study for the Union of Concerned Scientists and laid out some of the report's findings during a news conference yesterday at the New York Botanical Garden. "I hope you see from the findings of this report that emission choices really matter."

According to a preponderance of scientific research, heat-trapping emissions from burning fossil fuels as an energy source create a greenhouse effect that gradually warms the Earth's atmosphere. Tailpipe emissions and coal-burning electric power plants are two of the main pollution sources.

Researchers assumed two different scenarios in analyzing the future effects of climate change in the Northeast, working with a "business as usual" model and with a more aggressive approach to lowering carbon production.

"Our research shows clearly why ... our very way of life is at risk, particularly along our coasts," said Gary Yohe, a Wesleyan University economics professor who, like Frumhoff, participated in the high-profile 2007 Intergovernmental Panel on Climate Change that urged swift, worldwide action. "The question is: When do we start? The results show a very simple answer: That answer is now."

Frumhoff said that regardless of what is done from now on, the emissions already in the air and greenhouse gases already produced will bring about continued warming in the Northeast.

Unless changes are instituted, the report projects, winters and summers will be 10 degrees hotter by 2100 than now.

And if nothing is done to change behavior, these things are likely to happen in New York by the end of the century:

- The state's $1 billion skiing industry would be wiped out, basically from the lack of snow and cold.

- Long Island lobstering would cease, as the crustaceans seek colder climes to nest even more than they already do.

- Earlier springs that already stretch the growing season by four days might seem a help to farmers, except that shorter winters would suppress fewer insect pests and plant diseases, and hotter temperatures would bring droughts.

- Summers would rival those normally found in Georgia.

- High-water marks historically reached only every 100 years would be hit every 10 years instead because of increased storm activity and higher sea levels.

- Increased asthma and other health problems, including the West Nile virus and other insect-borne diseases.

- Greater vulnerability of watershed areas to the effects of longer and more frequent droughts, including dying vegetation that couldn't protect water supplies, and greater evaporation from the reservoirs.

Alexander "Pete" Grannis, the newly appointed commissioner of the state Department of Environmental Conservation, attended the release of the report.

"Obviously in this very compelling report, there's a great deal to think about and there's a great deal to worry about," said Grannis, whose agency is launching a state Office of Climate Change to work on the issue. "This puts a face on the impact of global warming on New York. For the average New Yorker, the issue can feel very remote ... that global warming doesn't really impact them. It isn't someone else's problem in some other place."