A new study in Nature magazine describes a new very-long-term temperature record assembled by a scientist at Stanford University from 61 different proxy climate records. Proxy records are climate records based on things like tree rings, ocean sediments and ice cores which change depending on climate factors like temperature. The new record shows temperatures for Earth in 5000 year increments going back 2 million years. While you can’t use these records to determine the actual temperature in any particular year, they can show long-term trends in climate over time. ABC News published an AP story linked to this study noting that based on this record the Earth is at the warmest as it has been in the last 120,000 years.
Other climate scientists are studying the reconstruction method to see if the temperatures match other independent temperature timelines. While you can’t read the original article due to the Nature paywall (unless you have a subscription), you can read the abstract if you are interested at https://www.nature.com/nature/journal/vaop/ncurrent/full/nature19798.html.
