New paper finds tropical Atlantic temperatures were up to 2.5C warmer 500-1000 years ago
'Paper published in PNAS finds from 2 sediment temperature proxies that upper 1,500 feet of tropical Atlantic Ocean experienced abrupt warming of about 3-4C during each of at least two periods over past 22,000 years due to a natural change in ocean oscillations [i.e. not greenhouse gases]. The paper also shows 'the modern mean annual temperature' is about 0.5 to 2.5C colder than the end of the proxy records around 500 years before the present'
