Our children and grandchildren will live on a “fundamentally different planet” by the end of this century unless people all over the world convince their governments and industries to stop global warming, warned Dr. Michael Mann, one of the nation’s leading experts on climate change.

How will the Earth be different in just 87 years? Mann predicted record heat waves.

Record crop-destroying droughts. Record wildfires --and not just in the West.

Expanding deserts. Storms producing more flooding. Rising ocean levels. And even more diseases, because fewer frosts will kill disease-carrying mosquitoes and ticks.

“We will see severe impacts regarding human health, water, energy and national security,” warned Mann. “The costs of inaction greatly outweigh any costs of taking action. We have to find a way to shift dramatically away from our current reliance on fossil fuel energy. In order to make sure we don’t leave behind a fundamentally degraded planet, we have to make those changes now.”

Speaking to more than 100 people at a program sponsored by the Mid- Atlantic Renewable Energy Association Tuesday night in Upper Macungie Township, Mann predicted if nothing is done average global temperatures will rise five to seven degrees Fahrenheit by the year 2100.

If you just look at land, it’s more than that,” said the director of the Earth System Science Center at Pennsylvania State University. “It’s probably closer to six to eight degrees over land. It’s larger than the difference in global temperature between the last ice age and today.”

He explained much of the globe is ocean and the ocean doesn’t warm up as much as land. He also said the Arctic will experience double the warming temperatures, as sea ice melts and the Arctic Ocean absorbs more warming sunlight.

But Mann said the impact of global warming will involve more than melting ice caps threatening polar bear habitat and rising ocean levels.

“Often we emphasize those far-off impacts too much,” he said in a brief interview after his lecture. “We talk about things that are going to happen in the Arctic to exotic creatures, when in fact things are going to happen right here in Pennsylvania.”

He said sea levels could rise six to nine feet by the end of the century. “We’re not talking the 20 feet that would be necessary to submerge Manhattan. But the Jersey Shore of my youth will not exist if we continue on this course.”

He added rising ocean levels also will mean more damaging storm surges, such as those generated by Hurricane Sandy in 2012.

Mann explained 2011’s slow-moving Hurricane Irene was not caused by climate change –“that storm could have happened anyway” – but it contained record amounts of water that produced flooding over eastern Pennsylvania and much of New England. That happened because the storm was spinning over an extremely warm ocean surface off the East Coast.

“The warmer the ocean’s surface, the more water vapor in the air above it. It’s very likely the near-record warmth of the ocean was responsible for the record flooding we saw.”

More than being framed by science, economics, policy or politics, Mann said climate change primarily is an issue of inter-generational ethics: “What sort of planet do we want to leave for our children and grandchildren?”

He hopes the day never comes when his daughter takes her children to a zoo, points to the polar bears and explains how they used to live in the Arctic “but we destroyed their home, we literally melted their home.”

Highest levels in four million years

In 2007, Mann was part of a group of scientists that jointly received the Nobel Peace Prize for the Intergovernmental Panel on Climate Change. In 2002, he was selected by Scientific American as one of the 50 leading visionaries in science and technology.

Mann maintained the scientific case for climate change is not complicated or controversial. He said it’s been known for nearly two centuries that greenhouse gases such as carbon dioxide have a warming influence on Earth’s atmosphere.

“The fact that we are increasing the concentrations of these gases in the atmosphere is not in dispute.”

“We are about to breach 400 parts per million of CO2 in the atmosphere,” said Mann. “We believe the atmosphere hasn’t seen CO2 concentrations that high in at least four million years. We’re talking about an unprecedented change in the composition of our atmosphere. And we know we are responsible for this build-up. It’s indisputable. It’s not coming from natural sources.”

“We only have one Earth and we are performing an uncontrolled experiment with that Earth.”

While the science and the threat are clear, he said: “We are a civilization that has been built on fossil fuels and is addicted to fossil fuels. And there are vested interests that profit from our dependence on fossil fuels and understandably probably don’t want to see that change.”

Mann said some of those powerful vested interests have launched a massive disinformation campaign against the science of climate change, much like the campaign once launched by the tobacco industry to try to convince the public there was no link between their products and human health.

He maintained global warming opponents have manufactured a controversy in a concerted effort to confuse the public. He said science is not a political issue with two equally valid sides.