This piece was originally published in Undark and appears here as part of our Climate Desk collaboration. Over four days last May, members of the Tk’emlúps te Secwépemc, a First Nations community in the interior of British Columbia, oversaw a site survey of around two acres of land surrounding the province’s former Kamloops Indian Residential School. Using an electromagnetic technology called ground penetrating radar (GPR), an archaeology professor charted what appeared to be the grave shafts of 215 children lying below the ground. The technology furthered the long-held suspicion that…