Reacción a "A study reveals temperature fluctuations of up to 25ºC over the past 485 million years"

The work developed by the Smithsonian Museum of Natural History (United States) and the University of Arizona (United States) provides a much more detailed view of how temperatures have varied over the past 485 million years (Phanerozoic) compared to what was previously known. To achieve this, the authors used a methodological approach based on data assimilation, in which they statistically combined more than 150,000 individual proxy data points (such as ice cores, tree rings, or marine sediments) with simulations from climate models. Data assimilation has been routinely used in numerical weather prediction by meteorological services for their operational forecasts, but its use in paleoclimatology has been very limited to date. This methodology provides a coherent view of the various variables that define the past climate and fills the gaps in time and space that are not covered by climate proxy data.

The novel use of this data assimilation technique in paleoclimatology has made it possible to establish the strong correlation between CO₂ concentration and the global temperature of the Earth throughout the entire Phanerozoic eon considered in this work, beyond the much-studied last 66 million years (Cenozoic). It has also established that temperature variations throughout the Phanerozoic are larger than previously estimated, with oscillations of up to 25°C in the Earth's global temperature, encompassing very cold periods of up to 11°C with large ice sheets and very warm periods of up to 36°C with no ice sheets. 

This work is a significant step toward better understanding past climates, helping to contextualize current climate change and future projections.