"Which of you, if your son asks for bread, will give him a stone?" (Matthew 7:9)

The answer Jesus expected was, of course, "No one!" If we reflect on our current situation, however, we cannot say that with any assurance. We are changing our climate, the relatively temperate climate of the last 10,000 years, and in a direction that promises tribulation and conflict for our descendants.

A statement like the above requires evidence and it is both plentiful and irrefutable. The basic physics has been known since the 19th century, and Svante Arrhenius described the greenhouse effect in 1896, predicting that carbon dioxide accumulating in the atmosphere from burning fossil fuels would heat the planet. That has been confirmed by directly measuring incoming and outgoing radiation that shows more coming in than going out. A survey of climate scientists showed that over 97 percent of them concur in the idea that humans are changing climate. What about the others? Unfortunately, scientists are only human and some of them may have been "bought" by the fossil-fuel industry.

What about people and organizations who profess skepticism about climate change or human capacity to alter the climate? There are several possibilities. Perhaps they have not really looked at the evidence or could not understand it. The more likely explanation is that their motives are suspect and that they have a stake in denying reality. They should not be called "skeptics"; they should be characterized as being "in denial," "delusional," or "divorced from reality."

Some could be characterized as corrupted by greed, like the Oklahoma senator, allied with the fossil-fuel industry, who claimed that snow in Washington disproved global warming. Many of these deniers have suspect motives and conflicts of interest, such as the fossil-fuel corporations who have spent millions of dollars to cloud the issue, using tactics honed by the tobacco companies to delay regulation of their deadly product.

Some say that climate change will take place in the far future and that we can use technology to prevent it. They are wrong. Unfortunately, global warming wreaks havoc now. As the atmosphere warms, it holds more water, leading to more energetic storms and worse flood events. Ask the people of Houston. Or ask the people of Puerto Rico, who still do not have basic amenities such as electricity and clean water completely restored from last year's hurricanes, as another hurricane season gets underway.

What is the evidence? Temperature is trending upward and 2014-2017 were the warmest four years since 1880. Research shows that tropical storms have slowed forward motion in recent decades, making flood events worse. Altered weather patterns create more intense heat waves and droughts, as well as floods. In 2003, at least 70,000 people died from an unprecedented heat wave in Europe.

Physiologists anticipate that it may become deadly to work outdoors in parts of the tropics if temperatures keep climbing. Foresters know that the dry period that creates the fire season in the American West has expanded since the 1960s. That's one reason massive wildfires have become so common. Disappearing mountain glaciers have become the norm, leading to increasing hardships and, potentially, wars over scarce water resources that billions of people rely on to drink, generate electricity and irrigate crops.

The polar ice caps that hold most of the fresh water on the planet are shrinking rapidly. Recently, it was discovered the Antarctic ice sheet is losing mass three times as fast as it was only a decade ago. The Arctic is already warming at least twice as fast as the rest of the planet, and the shrinking Greenland ice sheet holds enough water to raise sea levels 20 feet or more. The oceans are rising, and coastal flooding of some East Coast cities has become a regular event. Oceanic ecosystems themselves suffer, as increasing carbon dioxide raises water acidity. All over the world coral reefs hit by increased temperatures and acidity are dying.

What can we do to avoid a grim future which may already be at least partially unavoidable? We must get to zero carbon emissions as soon as possible.

China is transitioning to electric vehicles, nuclear power and renewable energy, and we ought to do the same. The most cost-effective way to draw down atmospheric carbon dioxide is with healthy forests, so reforestation and stopping deforestation must become a priority.

If we do not act effectively, urgently, what will our grandchildren say about us?

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Malcolm K. Cleaveland, Ph.D., is professor emeritus of geosciences at the University of Arkansas at Fayetteville. His areas of expertise include paleoclimatology and climatology.

Editorial on 07/09/2018