There are fears that such extreme summers in southern Europe will harm the tourist industry and also harvests, two mainstays of the economies of the region.
"Extreme natural phenomena are destroying the ecosystem and threatening our daily life, our way of life," said a statement signed by Italy's President Sergio Mattarella and his counterparts in Greece, Croatia, Slovenia, Malta and Portugal.
Large areas of the Mediterranean sweltered under an intense heatwave last month and firefighters battled to put out deadly blazes across a region stretching from Algeria to Turkey.
"There is no more time to waste, no more time to compromise for political or economic reasons," the presidents said in the statement, adding that the Mediterranean region was particularly exposed to the risks of water shortages and desertification.
The initiative was spurred by a telephone call between Mattarella and Greek President Katerina Sakellaropoulou, and then extended to other members of the "Arraiolos Group" of non-executive presidents from EU states.
"All Mediterranean countries must coordinate and react, engage in a collective effort to halt and reverse the effects of the climate crisis," the statement added.
The president in Italy plays a role in resolving political crises and tends to speak out in broad terms on wider social issues, while steering clear of partisan positions.
Thursday's statement sounded the alarm, but did not propose concrete remedies to try to deal with the issue.
The Italian government had no immediate comment on the presidents' statement.
