ST. PAUL, Minn. - A pre-eminent U.S. climate-change scientist is to speak tonight at the Science Museum of Minnesota.



While some climate change is normal, says Dr. Richard Alley, what's going on now is clearly man-made, since researchers have looked at all possible natural causes and found nothing.



"So, we can go down the list and say, 'Is there anything that could explain this other than us?' and we can't find it. Then we say, 'OK, but the physics of CO2 are really well known,' so we actually can see with high scientific confidence that our fingerprint is on the changing climate."



If the warming isn't stopped, says Alley, who has spent years researching the ice sheets in places such as Alaska, Antarctica and Greenland, a worst-case scenario would be the eventual flooding of the coasts.



"This one is getting to be very interesting, a little bit scary, but it's still difficult. We know that the ice sheets are contributing water to the ocean right now. It's not doing it very fast yet, but it's a really big pile of ice, and little pieces of it are changing in ways that are worrisome."



In other places such as Minnesota, Alley says, the changes would be a bit more subtle.



"Clearly, sea-level rise isn't going to get you as fast as it is going to get to people down in New Jersey, but eventually more record highs, fewer record lows, a little more water in the air so that when the rain cranks, it cranks a little more down on you. That kind of change is coming, if it isn't already here."



On the other side of the argument are those who say man-made climate change is a hoax. They say current models are not reliable enough to say what has caused changes in the past, much less project future climate.



Alley's lecture will begin at 7:30 p.m. at the museum. More information is online at smm.org.

