PETROLIA, CALIF. — Just after the West Coast's record-breaking temperatures eased this month, I hiked into the high country on the slopes of Washington's Mt. Rainier. Above alpine meadows dotted with lilies and Indian paintbrush, glaciers clung to the higher ridges.
They are the shrinking remnants of a chillier epoch on planet Earth, Ice Age vestiges that might disappear as the climate shifts under the influence of gases that industry and agriculture have put in the air.
As I traversed the alpine streams, I wondered whether the ice fields that feed them are destined to melt away in the next few decades, drying up these creeks as global overheating sets in.
Now Europe has taken a turn at sweltering, unheard-of heat, breaking all-time records across the Continent - from London to Turin, Italy. But the heat wave has left its mark on more than just the record books. Its impact has been measured in deaths from heat stroke, in power failures, and in thousands of acres of charred forest.
The damages are not confined to Europe: Weird weather - from the intense tornadoes that plagued the US Great Plains this summer to the mega-monsoon season that drenched India - has loosed itself on the planet in recent months.
As the costs to clean up the damage mount, it is worth revisiting the possibility that humans' inadvertent tinkering with the engines of climate has helped bring about this unusual weather.
We will never know whether the climate-altering gases emitted as a byproduct of our modern economy - chiefly carbon dioxide, but also methane and other trace substances - were wholly or partly responsible for this month's deadly weather. Day-to-day weather is so complex that the causes of individual storms and heat waves cannot be traced with certainty.
Instead, the disruption of the Earth's climate is best understood from the standpoint of risk.
The demand for utter certainty as a prerequisite for national action betrays a willful ignorance of the way climate works and, indeed, of the regularity with which we take costly steps to reduce risks even in the absence of certainty. Gambling with the climate increases the chance of catastrophe as surely as building in a flood plain.
Energy companies, too, may start to feel risk's hot breath. As the link between emissions and climate disruption becomes better established, the stage is being set for a host of product-liability and nuisance lawsuits. Under common law, parties who have experienced a nuisance may sue those who caused it. That was how farmers in California's Sacramento Valley put an end to hydraulic mining for gold in the 1880s, after the tailings from mines upstream entombed their land under a thick layer of gravel and silt.
"Nuisance is an unreasonable interference with the use of land or other property," explains John Echeverria, executive director of the Georgetown Environmental Law and Policy Institute. "In theory, there are certainly ways in which you could frame a nuisance action based on global warming." When the effects of climate change spreads, the list of plaintiffs could grow long. Citizens of low-lying island nations such as Tuvalu that may vanish beneath the waves as melting ice raises sea levels might consider themselves wronged. So, too, might farmers whose agricultural land is devalued because of droughts, beachfront property owners who must build sea walls or lose their land, and so on.
The courtroom is a messy arena to settle these issues, however, because of the number of potential plaintiffs and the difficulty of apportioning blame among the myriad possible defendants.
Instead, the more promising way to limit climate change is through an international treaty that would set goals for lower emissions and establish systems to make this transition more efficiently.
This month is an encouraging time to consider that prospect, with recent news of humanity's success in deflecting another global threat that was inadvertently brought on by industrial progress: the thinning of the ozone layer. A decade and a half after the Montreal Protocol established the precedent of treaties to control a worldwide threat to the atmosphere, researchers noted a slowing in the loss of ozone - a gas found in the upper atmosphere that shields living beings from the harmful effects of ultraviolet rays.
It is time to build on that experience and apply it to the problem of climate, so that tomorrow's hikers traipsing around Mt. Rainier will see alpine meadows and remnant glaciers, not sagebrush and desert.
• Seth Zuckerman writes on environmental issues for Tidepool.org. He is a graduate of the Energy and Resources Group at the University of California at Berkeley.