By Mary M. McKenzie

I have just returned home to San Diego from the 36th training session of the Climate Reality Project’s Leadership Corps in Pittsburgh, Pennsylvania. I am now part of a group of about 13,000 trained leaders across the globe with the commitment to speaking the truth about the realities of climate change, also known as global warming.

This specific movement dates back 11 years to the release of former Vice President Al Gore’s film, “An Inconvenient Truth.” Yet there is still significant resistance to the idea that we humans are heating the Earth beyond its capacity to host living forms as we know them.

In part, this is because of the complexity of the physical mechanisms involved; there exists a complex web of factors that, combined, are changing the basic climate patterns of the planet. For those of us who are not geologists, physicists, biochemists or climate scientists, these patterns are quite challenging to understand.

Perhaps more importantly, the idea that we are actively helping to kill the planet scares us, especially if we have children or grandchildren. Closing our eyes to the facts, though, doesn’t make them go away. We are actively killing this planet that sustains us.

Has the Earth gone through climate cycles before? Absolutely, yes. One killed off the dinosaurs. But the current cycle is the only one marked by human activity that has significantly altered the natural balance in the atmosphere.

Have you noticed this storm season (hurricanes Harvey, Irma and Maria) included Tropical Storm Ophelia that reached Ireland? How about the deadly wildfires in California, Portugal and Spain? Or the disappearance of ancient glaciers in the Arctic and Argentina? This is not normal; it is caused by the extraordinary heating of the air and the oceans and a fundamental shift in the Gulf Stream. There is no scientific doubt about this, unless you believe that the over 2,000 esteemed scientists who are part of the Intergovernmental Panel on Climate Change are wrong or want to dupe us. Scientific uncertainty exists, but not here.

Is there anything we can do? Cleaning up after ourselves will be difficult, and things will not turn around quickly. However, we must end our reliance on coal, oil and gas, which is the chief human contributor to carbon dioxide emissions. This is what is warming our planet, raising sea levels — part of Greenland has disappeared! — and changing the basic terrain of large swaths of the world.

Climate change is not a joke, a hoax or a false alarm. We can change the outcome. But we need to do it now.

To learn more about the Climate Reality Project (CRP), visit bit.ly/2y3GFD7.

I plan to establish a CRP chapter in San Diego in the near future. Additionally, San Diego is home to several forward-thinking environmental action groups that would welcome your involvement, including the Climate Action Campaign (climateactioncampaign.org) and SanDiego350 (sandiego350.org).

—Dr. McKenzie is an adjunct professor of political science at the University of San Diego. She also serves as the secretary of the Hillcrest Town Council. She can be reached at [email protected].