The signs of climate change are everywhere, Lehigh professor Dork Sahagian warned the audience at the Great Decisions lecture Feb. 5. The amount of carbon dioxide in the atmosphere is on an extreme upward curve; average global temperatures set a record the last four years; the amount of ice in the Artic set an all-time low in 2007, and was tied for second last year; on Feb. 25, 2018, the temperature at the North Pole was above freezing in the winter for the first time ever.

“We’re on a trajectory of higher temperatures,” said Sahagian, a professor of earth and environmental science. Right now, globally, more CO2 emissions come from coal than from any other source. He spent a large portion of his lecture describing what will happen if no action is taken to slow climate change.

Sea levels will rise, wet places on earth will get wetter, while dry places will get drier, and there will be warming of .2 degrees centigrade per decade. Already, he said, the sea ice in Greenland is melting much faster than had been predicted. The inevitable results if current trends continue will be more frequent and stronger coastal storms, a drop in the production of grains worldwide, and, as a result of warming oceans, a change in worldwide shipping lanes which will shift power to more northern countries, including Canada, Russia and the Scandinavian countries.

It will also lead to a migration northward, he said, joking, “Canada’s going to build a wall.”

Despite the changes already happening, and despite the warnings of scientists, he said, there has been no political discussion about how to mitigate the effects of these changes.

“We have to alter our mindset,” he said. Right now, “we’re consumers, not preservers.”

He said there have been some efforts in this area to address the problem. Philadelphia, he said, is under pressure to use more natural gas than other fossil fuels such as coal, and PECO’s energy sources are already non-fossil fuel derived.

But right now, “any solution will be negated by population growth,” he said.

He said the Kyoto Protocol, which was adopted in 1997, but not signed by the United States, while pledging to reduce greenhouse gas emissions to 1990 levels, is not enough.

The 2015 Paris Agreement to cut emissions, which was signed by more than 190 countries, was not much better, he said, and President Trump has pulled the U.S. out of that agreement.

China has plans to reduce emissions per GDP by 60 percent, he said, but even that won’t be enough, because their GDP is going up. Right now, he said, China emits by far the most carbon dioxide of any country, but not the most per capita.

“We know things are going to get worse,” he said, but the question is “by how much?”

He said he doesn’t like to say there is no hope, but warned there will have to be cooperation among countries, if anything is going to change the current trajectory.

The Great Decisions foreign policy lecture series is held 11 a.m.-12:30 p.m. Wednesdays from now until March 25 in the auditorium at Kirkland Village. It is sponsored by the Bethlehem YWCA. The Feb. 12 lecture is on “U.S. Relations with the Northern Triangle” of Central America. The Feb. 19 lecture topic is “Artificial Intelligence and Data.”