One month after the second part of “Ecologies of Peace” opened in Cordoba, much of Spain was underwater. On October 29, more than an average year’s rain fell along the country’s southern and eastern coasts, killing over 200 people. Days later, crowds in Valencia pelted King Felipe VI and Prime Minister Pedro Sánchez with mud, blaming them for the state’s lack of emergency preparedness. The worst natural disaster in a generation became a political crisis. If the ruling classes continue to prove themselves unwilling to address the climate emergency, then it’s fair to say that artists aren’t going to save the world either. But this show at C3A proceeds from the limited if hopeful assumption that they might be able to make a difference. Half of a group exhibition in two acts, “Ecologies of Peace” emerged from a series of partnerships between TBA21 and underfunded regional institutions, and at first glance, its title shares a sunny vagueness familiar from biennials in other parts of the world. Curated by Daniela Zyman, it claims to focus on “practices of mourning and forgiveness,” though, for the most part, it illustrates the scale of the devastation that calls for them. “One has to learn …