Potential grading refrigeration system? Based on urban agglomeration thermal environment analysis perspective

•Addressing urban thermal environment stress from a natural perspective.•The MCR model was used to extract potential cooling corridors.•Constructing a graded cooling system for urban agglomeration from 2005 to 2020.•Thermal environment intensity of the BTH urban agglomeration has increased.•The robustness and connectivity of the cooling system have both been enhanced.