Gilbertson uses professional surveying equipment such as
GNSS receivers to precisely find the elevation of mountain summits. In 2018, Gilbertson climbed Jabal Sawda, which was previously believed to be the high point of
Saudi Arabia, but determined that it was shorter than
Jabal Ferwa. and
Uzbekistan. In 2024 he was awarded a grant by the
American Alpine Club to survey the
Cascade Range in Washington state to determine how Washington's mountains were being impacted by climate change. to track ice melt over time. He first reported the findings on
Mount Rainier in 2024. Larry Signani, who first surveyed the mountain for the
Army Corps of Engineers, told
The Seattle Times that the results were credible. concluded that four of the five—Mount Rainier,
Eldorado Peak,
East Fury, and
Liberty Cap—had lost around of ice.
Colfax Peak had maintained its elevation and it, along with Liberty Cap, remained the only ones that still had ice on the summit year-round. The findings, published in 2025, indicated that the ice melt is attributed to climate change and an increase of temperature of nearly since the mid-twentieth century, with most of this increase happening since 1990. On October 5, 2025, Gilbertson surveyed
Crestone and
East Crestone peaks in Colorado, determining that East Crestone is high, and around taller than Crestone, which was previously considered the true summit of the Crestone cluster. He showed that where LiDAR indicated there was a
spire on East Crestone's summit, there wasn't any such feature. As to the discrepancy between their heights, he said that "The simplest explanation is they just hadn't been measured accurately enough until now to know which was taller". == Select publications ==