Within a few decades, Park City skiers may have to make sure they have a trusty pair of rock skis — the snow pack might not be all that impressive at the beginning and end of the ski season.

A scientist on Wednesday night told an audience at the Eccles Center that the snow pack will be reduced enough at the lower elevations of mountain resorts by 2030 that a week at the beginning and a week at the end of the ski season could be lost to climate change.

Twenty years after that, the ski season might start up to two weeks later and end one or two weeks earlier.

Brian Lazar, a scientist from Colorado, issued a dire projection for the ski season by late in the century — there might not be enough snow by 2075 to maintain the ski season as it is today.

“Winter looks different,” Lazar told the crowd, adding that Utah’s famous dry, powdery snow will more frequently resemble “Sierra cement” by then.

Speaking at an event dubbed Save Our Snow II, the second major gathering of Parkites trying to combat a warming planet, Lazar said the Intermountain West’s temperatures are climbing more quickly than elsewhere in the U.S. and the warming has accelerated since 1970.

He projected temperatures in the Park City area will rise between 2 and 3 1/2 degrees Fahrenheit by 2030 and by between 3 and 5 degrees Fahrenheit by 2050. The temperatures could be between 5 and 9 degrees Fahrenheit hotter by 2075, depending on the amount of emissions spewed in to the air, he said.

“All the models predict warming,” Lazar said.

The Eccles Center event was held as City Hall, the local ski industry, businesses and regular Parkites are continuing their efforts to reduce emissions believed by many to contribute to a changing climate. The programs in Park City vary widely and include choosing to use cleaner-burning energies like biodiesel fuel in vehicles and heating systems that rely on the internal temperature of the Earth. Local leaders say Park City’s long-term viability as a mountain resort depends on cold, snowy winters.

Meanwhile, the economic losses in the Park City area could mount if the projections are accurate.

David Chapman, a colleague of Lazar who studied the impact on the economy, said the change in the weather could cost Park City’s economy $120 million by 2030. The ski industry now generates $900 million each year in business, he said. 2050, the cost to the economy could reach between $160 million and $392 million each year, he said.

Chapman said 1,137 local jobs could be lost by 2030, with the numbers rising to between 1,520 and 3,717 by 2050.