Researchers at NIOZ, the Universities of Utrecht, and Bristol have found that a doubling of CO2 in the atmosphere could lead to a temperature increase of up to 14 degrees, much higher than previous estimates by the IPCC. By analyzing sediments from a 45-year-old drill core in the Pacific Ocean off the coast of California, the researchers were able to track changes in temperature and CO2 levels over the past 15 million years. The results, published in Nature Communications, suggest a strong relationship between CO2 concentration and temperature, with the average temperature being over 18 degrees 15 million years ago, much warmer than today.
The researchers used a new approach to derive past atmospheric CO2 levels by examining the chemical composition of substances found in algae, such as chlorophyll and cholesterol. Algae absorb CO2 from the water and fix it through photosynthesis, creating fossils that can be analyzed to determine CO2 content. By measuring the ratio of 13C and 12C in these substances, the researchers were able to track changes in CO2 concentration over millions of years. They found that CO2 levels have decreased from 650 parts per million 15 million years ago to 280 just before the industrial revolution.
The study also utilized the TEX86 method, developed at NIOZ, to estimate past seawater temperatures based on the composition of archaea membrane substances found in ocean sediments. By combining these temperature estimates with CO2 levels derived from algae substances, the researchers were able to create a unique time series of temperature and CO2 fluctuations over the past 15 million years. This approach has provided valuable insights into the impact of CO2 concentration on global temperature and offers a warning about the potential consequences of inadequate CO2 emission reduction measures.
The research indicates that the relationship between atmospheric CO2 levels and temperature is stronger than previously thought, with the average temperature 15 million years ago being 4 degrees warmer than today. This suggests that without significant efforts to reduce CO2 emissions and implement technological innovations to offset them, the planet may experience much higher temperature increases in the future. The study highlights the urgent need for action to address climate change and underscores the importance of accurately predicting the impact of CO2 concentration on global temperature to inform policy and decision-making.
By analyzing a 45-year-old drill core from the Pacific Ocean, researchers have provided new insights into the relationship between CO2 concentration and global temperature over the past 15 million years. The study’s findings suggest that a doubling of CO2 in the atmosphere could lead to a temperature increase of up to 14 degrees, much higher than previous estimates by the IPCC. By combining temperature estimates derived from archaea membrane substances with CO2 levels derived from algae fossils, the researchers were able to create a unique time series of temperature and CO2 fluctuations, highlighting the strong impact of CO2 concentration on global temperature.
This research provides a warning about the potential consequences of inadequate CO2 emission reduction measures, emphasizing the urgent need for action to address climate change. The study’s findings suggest that the relationship between atmospheric CO2 levels and temperature is stronger than previously thought, with the average temperature 15 million years ago being 4 degrees warmer than today. This underscores the importance of accurately predicting the impact of CO2 concentration on global temperature to inform policy and decision-making and highlights the need for significant efforts to reduce CO2 emissions and implement technological innovations to offset them.
