Scientists have been keeping an eye on ice caps of the South and North poles for several years as any changes in this part of the world could impact the entire earth. But now they said that there will be a gap of several years in their ability to measure the thickness of the ice, as the two satellites dedicated to observing the poles are about to die before sending the replacements.

This could leave the scientists completely unaware of the changes occurring in both the poles as the climate warms up. The researchers expressed their concerns about the situation to the European Commission (EC) and the European Space Agency (ESA).

A Letter to ESA and EC

Satellite images show the effects of a prolonged warm spell on Eagle Island, in the far north of the Antarctic Peninsula, NASA says.
Satellite images of the Antarctic Peninsula NASA

A letter that included the problems and possible solutions was sent to EC and ESA officials this week. Even though NASA is not there as a recipient of the letter, the US space agency has been made aware of the issues related to the longevity of the European CryoSat-2 (launched in April 2010) and American ICESat-2 (launched in September 2018) missions.

Both the satellites carry instruments, knowns as altimeters that measure the shape and elevation of the ice surface in the Arctic and Antarctica. The satellites at 88 degrees north and south from the equator, which means they can see the entire Antarctic and Arctic regions, bar a small circle about 430 kilometers in diameter at the poles themselves.

This is what makes both the satellites unique, as most other satellites don't usually go above 83 degrees. The scientists are worried as both the satellites will have to be decommissioned long before any follow-ups are launched and as a consequence, the scientists wouldn't be able to access any data on the poles.

In the letter, scientists noted, "Without successful mitigation, there will be a gap of between 2 and 5 years in our polar satellite altimetry capability. This gap will introduce a decisive break in the long-term records of the ice sheet and sea ice thickness change and polar oceanography and this, in turn, will degrade our capacity to assess and improve climate model projections."

The EC has initiated the CRISTAL polar altimeter as a high priority mission along with the ESA. But as per the letter, the earliest launch date for this mission is in the final quarter of 2027. It could delay also as full funding to make this timeline a reality is not yet in place.

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What About NASA?

Nearly 600 scientists have signed the letter and just over 10 percent are American scientists. The signatories to the letter sent to EC and ESA include the scientists who have been using the data gathered from CryoSat and ICESat, as well as the president of the International Glaciology Society, and lead authors on the UN's Intergovernmental Panel on Climate Change.

Dr. Thomas Zurbuchen, the head of science at NASA, is not being sent the letter but he is aware of it. He said that he is hopeful that any polar gap could be solved or minimized. "I think there are multiple options at this moment in time that we can deploy to that end, in a partnership or otherwise," he added.

To make sure the continuity of polar altimetry, there is an urgent need to consider mitigation measures. As per the letter, "Possible solutions include extending the lifetime of CryoSat-2 or ICESat-2, maneuvering an alternative satellite into a high-inclination orbit, accelerating the launch of CRISTAL, and initiating a systematic airborne measurement program as a bridging capability."

Scientists believe that the cost of developing the airborne radar altimeter could be accomplished for around $5,982,000, but its design and the further process would likely take two years.