The Sugarloaf Fire grows in the Williams Fork Range, Thursday, June 28, near Silverthorne. The fire was one of many wildland fires in the High Country this summer and fall as the impact of climate change starts to become truly known in the region.

Hugh Carey / hcarey@summitdaily.com

Climate change is beginning to have the devastating impacts on America long predicted by scientists, and without action to mitigate or adapt, the country is in peril. That’s according to the latest National Climate Assessment, a major “report of reports” commissioned by President Donald Trump and Congress to study the impacts climate change is having on American communities.

The National Climate Assessment, which is updated every four years as mandated by law, made clear that human-caused climate change is not only real, but that we are already living through its impacts. Extreme hurricanes, wildfires, droughts and other adverse weather conditions are already happening, and will continue to get worse.

While the report may seem like a mere reaction to recent extreme weather caused by climate change, it was written long before the devastating hurricanes Florence and Michael in the southeast, and mega-wildfires across the West through summer and fall. The report predicts thousands of annual deaths in cities across the country by the end of this century due to extreme weather events like the ones we saw this year. Extreme cold and heat, as well as the spread of pest insects like the mountain pine beetle and insect-borne diseases like Lyme, also will cause misery and death.

Aside from the physical destruction wrought by extreme weather, climate change also will have a cumulative financial impact on communities that will start to cripple the national economy as a whole. According to the report, by 2090 the country will see an average of $280 billion in annual economic losses if warming is kept to a “moderate” level. However, if no changes are made to greenhouse gas emissions, the resulting “extreme” warming will cost the country an eye-popping $500 billion a year.

This year’s report emphasizes how different societal functions — such as water, transportation, energy, health care and other critical systems — are all interconnected, and how an impact on one system can cripple others.

The report used the massive damage wrought by 2012’s Hurricane Sandy on New York City as an example of how an entire system can be shut down by damage to one or multiple critical municipal functions. Flooding in tunnels and subways caused massive disruption to the city’s electrical grid, while hospitals were shut down and raw sewage gushed out of flooded sewers.

When it comes to Colorado and the rest of the Southwest, water is a primary concern in the report.

“Water for people and nature in the Southwest has declined during droughts, due in part to human-caused climate change,” the report said. “Intensifying droughts and occasional large floods, combined with critical water demands from a growing population, deteriorating infrastructure and groundwater depletion suggest the need for flexible water management techniques that address changing risks over time, balancing declining supplies with greater demands.”

The report points out that Lake Mead on the Colorado River, a primary water reservoir for the West, has seen water levels drop by 130 feet and has lost 60 percent of its volume since 2000 due to ongoing droughts and increased water demands. Precipitation shortages, which have already had an impact on local economies, will gradually have more and more detrimental impacts on everything from agriculture to tourism in the region.

The problems will continue to magnify as the Southwest continues its breakneck growth — the region is growing 30 percent faster in population than the rest of the country.

While all of this sounds dire, the report does offer hope that impacts of climate change can be mitigated, even if it is too late to avoid them entirely. The primary recommendation to start mitigating the impact of climate change is for communities to adopt adaptation strategies.

Adaptation involves spreading awareness of concerns related to climate change, assessing the situation, plan based on the best available information available, implementing those plans, then monitoring and evaluating results.

Local governments will be the primary driver of adaptation strategies, but will come with price tags that seem far too steep to the average taxpayer. The report states that the best way local government can “sell” these adaptation strategies is to present cost-benefit analyses of mitigation policies, as well as to incorporate “iterative risk management” that constantly assesses and tweaks climate change strategy over time, rather than follow a single static strategy planned and implemented without adapting to future conditions and needs.

In Summit County, aggressive fire mitigation and forest management strategies can be seen as a continuing adaptation to an increasingly hostile environment. Work between state and local governments to address water wastage through more rigorous management has also seen positive results in conserving water.

The other recommendation to mitigate climate change impacts is to reduce greenhouse gas emissions, particularly carbon dioxide and methane.

“Recent studies also show that many climate change impacts in the United States can be substantially reduced over the course of the 21st century through global-scale reductions in greenhouse gas emissions,” the report said.

Many communities across the country have already adopted mitigation strategies. Summit County, for one, has adopted several resolutions to curb greenhouse gas emissions.

However, if these strategies are not implemented at a higher level, and nationwide, climate change may be more harmful to the American economy and natural environment than any natural or man-made disaster in the Republic since its inception.

“Under scenarios with high emissions and limited or no adaptation, annual losses in some sectors are estimated to grow to hundreds of billions of dollars by the end of the century,” the report warned. “It is very likely that some physical and ecological impacts will be irreversible for thousands of years, while others will be permanent.”

Sen. Michael Bennet issued a statement responding to the study’s conclusions, and called for the current administration to respond to its own study with action.

“The National Climate Assessment puts more facts behind what Coloradans have known for years,” Bennet said. “From persistent drought to reduced snowpack to raging wildfires, our state’s farms, mountain towns and cities all feel the effects of climate change. And those effects take a real toll on Colorado’s economy. I’m glad to see the Trump administration is finally acknowledging the science behind our changing climate — now it’s time they act on it.”