▁problems ▁for ▁the ▁Illinois ▁Water way , ▁which ▁car ries ▁ 2 5 ▁million ▁tons ▁of ▁cargo ▁per ▁year ▁between ▁Chicago ▁and ▁the ▁Mississippi ▁River ". ▁ ▁Great ▁L akes ▁ ▁" The ▁ice - free ▁season ▁along ▁the ▁Great ▁L akes ▁is ▁also ▁becoming ▁longer . ▁Between ▁ 1 9 9 4 ▁and ▁ 2 0 1 1 , ▁reduced ▁ice ▁cover ▁length ened ▁the ▁sh ipping ▁season ▁on ▁the ▁la kes ▁by ▁eight ▁days . ▁The ▁Great ▁L akes ▁are ▁likely ▁to ▁warm ▁another ▁ 3 ° ▁to ▁ 7 ° F ▁in ▁the ▁next ▁ 7 0 ▁years , ▁which ▁will ▁further ▁extend ▁the ▁sh ipping ▁season ". ▁ ▁" In ▁Lake ▁Michigan , ▁changing ▁climate ▁is ▁likely ▁to ▁harm ▁water ▁quality . ▁War mer ▁water ▁tends ▁to ▁cause ▁more ▁alg al ▁blo oms , ▁which ▁can ▁be ▁uns ight ly , ▁harm ▁fish , ▁and ▁deg rade ▁water ▁quality . ▁Se vere ▁storm s ▁also ▁increase ▁the ▁amount ▁of ▁poll ut ants ▁that ▁run ▁off ▁from ▁land ▁to ▁water , ▁so ▁the ▁risk ▁of ▁alg al ▁blo oms ▁will ▁be ▁greater ▁if ▁storm s ▁become ▁more ▁severe . ▁In cre asing ly ▁severe ▁ra inst orm s ▁could ▁also ▁cause ▁se wers ▁to ▁overflow ▁into ▁the ▁lake ▁more ▁often , ▁threaten ing ▁beach ▁safety ▁and ▁drink ing ▁water ▁supplies ". ▁ ▁Agricult ure ▁ ▁" Ch anging ▁climate ▁will ▁have ▁both ▁benef icial ▁and ▁harm ful ▁effects ▁on ▁far ming . ▁Long er ▁fro st - free ▁growing ▁seasons