Understanding the earth system responses to current rapid climate change requires comprehension of past abrupt climate variability at centennial-to-millennial timescales. Despite increased efforts to understand this variability, several questions remain open, especially related to tropical and subtropical climate forcing and responses. This special issue is centred on the signature of abrupt climate change in the American tropics and subtropics and focuses on ocean, atmosphere and biosphere records. It is produced by the Latin-American Abrupt Climate changes and Environmental Responses (LaACER) initiative, a project of the Palaeoclimate Commission of the International Union for Quaternary Science (INQUA).