The chorus of global warming deniers has not shrunk. Outcries claiming the entire issue is fraudulent are not going away.

But realism is also slowly setting in among some California groups that long tried to wish away the issue by claiming any warming that’s happening is strictly a cyclical natural phenomenon.

California ranchers are now among the first interest groups to realize that like it or not, global warming can no longer be denied with any semblance of accuracy. For very gradually, ranchers are seeing the grasslands they depend upon to feed their cattle begin to shrink and convert naturally to shrub land.

What’s the difference? Shrubs have a greater ability to withstand wildfires, but cattle don’t like to eat them. This means the more grasslands gradually shift to chaparral-like shrubbery, the more ranchers must spend on hay. For consumers, that means more expensive beef, from filet mignon to hamburger.

It’s not that grassland is disappearing quickly or that the loss is inevitable. But there has already been some acreage lost, mostly in the foothills of the Sierra Nevada mountains and a 2013 study from Duke University and the Environmental Defense Fund concluded that if global warming continues its present trends, it will hike California ranchers’ spending on hay by upwards of $235 million a year within the next half century.

Climate change denial tends to run stronger among political conservatives than others, so an interesting contradiction is arising. For these are usually the same folks who oppose increasing national debt levels for fear of fobbing large burdens onto generations to come. Why, then, do they not mind hitting those same generations with an environmental calamity?

Maybe because they don’t believe there’s anything humans can do about global warming. They ignore, though, the hundreds of academic studies that have found increased atmospheric levels of carbon dioxide (CO2) are associated with higher ambient temperatures.

Maybe, also, they don’t think a degree or two of difference in average temperatures makes much difference. The once-large and permanent icefields visible from Glacier Point in Yosemite National Park offer some evidence to the contrary: Photographed a century ago at midsummer by the legendary Ansel Adams and others, they are now all but gone.

So even if the warming visible on rangelands and high mountain peaks were mostly from natural causes, it is helped along by human activity that produces CO2. Which means today’s adults have an obligation to their children to do whatever they can to contain it.

One officer of the California Cattlemen’s Association, which just over two years ago issued a statement opposing all cap-and-trade legislation, later said in a rangeland conference at UC Davis that climate change (natural or not) is “certainly going to impact all the other natural resources that we’ve worked to steward for so many years.”

This change of attitude toward climate change from an organization that’s anything but politically liberal was remarkable.

Whether it presages movement among other interest groups that have consistently fought climate change legislation is an open question. But it demonstrates that ideology can sometimes go out the window when confronted with hard reality.

Thomas D. Elias is a writer in Southern California. tdelias@aol.com