Learning global solidarity in the Covid-19 pandemic?

In a letter published on March 30, 2021, 24 world leaders have called for global solidarity in the fight against the Covid-19 pandemic. This commitment to act in solidarity with low-income countries however was won under duress, and it was in part at least self-serving. Can this still be called solidarity? On the basis of a functional view on solidarity the paper argues that states can indeed act in solidarity, if they accept costs to assist others with whom they recognize similarity in a relevant respect. States can act in solidarity, or they can fail to act in solidarity, also in situations of duress and if solidary acts also serve their own interests. The paper concludes that if this is true for the Covid-19 pandemic it is also true for the climate crisis, where damage of even much bigger dimensions are to be prevented. Also in regard to anthropogenic global heating, nobody is safe until everyone is safe.