This article lists a number of significant events in science that have occurred in the second quarter of 2021.
Events
April
2 April – Scientists report that the event that caused the mass-extinction of dinosaurs gave rise to neotropical rainforest biomes like the Amazonia, replacing species composition and structure of local forests. During ~6 million years of recovery to former levels of plant diversity, they evolved from widely spaced gymnosperm-dominated forests to the forests with thick canopies which block sunlight, prevalent flowering plants and high vertical layering as known today.
6 April
A study finds that carbon emissions from Bitcoin mining in China – where a majority of the proof-of-work algorithm that generates current economic value is computed, largely fueled by nonrenewable sources – have accelerated rapidly, would soon exceed total annual emissions of European countries like Italy and Spain in 2016 and interfere with climate change mitigation commitments. COVID-19 pandemic: Scientists report the "estimated incidence of a neurological or psychiatric diagnosis in the following 6 months" after diagnosed COVID-19 infection was 33.62% with 12.84% "receiving their first such diagnosis" and higher risks being associated with COVID-19 severity.