With climate change, practically everything is changing, and it is not always the great upheavals that should concern us. Subtle changes in us and nature, for example, have hardly been noticed so far, apart from the fact that the creeping evolution of loudmouths has noticeably accelerated with rising world temperatures.

Even if it is not yet immediately apparent to many of them, the correlation with the well-documented beak growth in Australian parrots can be derived somewhat plausibly: Large beaks ventilate more strongly. However, not everything is getting bigger.

The whistling frogs of Puerto Rico, for example, which are a national symbol and known beyond the island because of their two-syllable, deafening call, are currently experiencing a voice break. The smallest frogs with the highest and loudest voice are drawn up the mountains. There they displace the larger conspecifics, which are adapted to the cooler alpine regions but are lazier in their voices. Until at some point, perhaps, the hooting up there will stop, because the rising heat is also sizzling their brood. Climate change is merciless.

As far as birdlife is concerned, it's hardly any different. In a meta-study of 104 bird species, researchers have found a decline in the number of offspring and a reduction in the population by more than half in half a century. And again: The little ones get through better. In general, the direction of evolution already seems clear.

Many bird species tend to become smaller in body as they warm, as indicated by a long-term study published in the journal "PNAS" in North and South America. Everything is shrinking. To start screaming. However, even such a dubious prospect is unlikely to silence the climate-skeptical speakers.