I hadn't realized it was based on concrete measurements of what the paleoclimates — the ancient climates — were, as recorded in the ice sheets, as recorded in deep ocean sediments, as recorded in lake sediments, tree rings, and a lot of other ways of measuring temperature.
No me había percatado que era basado en medidas concretas que eran los paleoclimas — los climas del pasado — tal y como se registra en las capas de hielo, en los sedimentos del fondo del océano, en los sedimentos de lagos, anillos de árbol, y muchas otras formas de medir la temperatura.