Summit Station, 10,530 feet above sea level on the Greenland ice sheet, is more than 260 miles from land. In the winter, when the sun does not rise from mid-November until late January, temperatures can dip to minus 50 degrees Fahrenheit, and winds can exceed 60 miles per hour.

This remote outpost is one of several Greenland sites where researchers from around the world gather data that will improve climate models and help predict climate change affecting future generations. Greenland’s ice sheet holds one of the largest freshwater deposits on the planet; scientists estimate that its full melting could raise sea levels by more than 20 feet.

Summit Station offers access to a trove of data for the dozens of scientific researchers at this remote outpost. Twice a week throughout the year, braving the punishing conditions, Hannah James, a science technician for a logistics company called Polar Field Services, hikes almost a half-mile away from the station to an area with pristine air. Once there, she puts on a so-called clean suit, designed to keep the environment as sterile as possible, then walks an additional 300 feet to collect a snow sample.

Getting to research sites in Greenland is difficult, and many are accessible only by air. Planes like the LC-130, mounted with skis to land on snow and ice, are lifelines for the researchers. The first stop is usually Kangerlussuaq, a tiny town of about 500, which serves as a staging point for researchers before they head out to do their field studies.

One dirt road, lined with research camps, leads out of Kangerlussuaq. The road snakes along the Akuliarusiarsuup Kuua River, past the Russell Glacier, and passes fields where melted permafrost has caused the ground to buckle and shift. After more than 18 miles of bumpy travel, the road abruptly dead-ends at the edge of the Greenland ice sheet. This area, named Point 660, serves as a base for many research projects each year.

With the Russell Glacier in the background, Jessica Trout-Haney and Zachary Wood used nets to capture insects in order to analyze biotoxins found in them, and how those toxins move through the food web. Greenland’s warming could lead to new forms of toxic cyanobacteria thriving where they previously could not.

On the ice cap, Grace Andrews and Josh Unterman collected samples from a stream of meltwater flowing across the ice sheet in order to measure the amount of carbon dioxide in the water. Ms. Andrews is researching whether the carbon dioxide in the stream is derived from an ancient carbon source, sequestered and stored in the ice for thousands of years. If so, as the ice sheet melts, some of this ancient carbon is being released. Current climate models do not account for that.

The meltwater winds through rivers and fjords, flowing toward the ocean, where it merges with towering icebergs.

The Ilulissat Icefjord displayed the intersection of the ice sheet, calving glaciers and rising sea levels. Sediment generated from the grinding glacier is pushed out to sea with the meltwater, forming a contrasting plume in the fjord.

The ice ruptures from the Jakobshavn Glacier, one of the most active in the world, seen through the cockpit of a low-flying LC-130 as it leaves Summit Station.