Researchers have found that the rate of atmospheric carbon dioxide increase today is 10 times faster than at any other point in the past 50,000 years. This finding, published in the Proceedings of the National Academy of Sciences, sheds light on abrupt climate change periods in Earth’s history and provides new insight into the potential impacts of climate change. The study, led by Kathleen Wendt of Oregon State University, highlights the unprecedented rate of CO2 change driven largely by human emissions.
Carbon dioxide is a natural greenhouse gas that contributes to climate warming when it enters the atmosphere. While CO2 levels have fluctuated in the past due to natural causes such as ice age cycles, they are currently rising because of human activities. By analyzing ancient Antarctic ice cores, scientists can track past climate changes and understand the historical patterns of CO2 levels. The research, supported by the U.S. National Science Foundation, reveals the fastest rates of natural CO2 rise ever observed, with today’s rate being 10 times higher.
Previous studies have shown that during the last ice age, there were periods where carbon dioxide levels spiked significantly higher than average, known as Heinrich Events. By examining samples from the West Antarctic Ice Sheet Divide ice core, researchers identified a pattern linking these jumps in CO2 levels with North Atlantic cold intervals associated with abrupt climate shifts globally. These events were likely caused by the dramatic collapse of the North American ice sheet, leading to a chain reaction involving changes in tropical monsoons, Southern hemisphere westerly winds, and CO2 emissions from the oceans.
During the largest natural rises in CO2 levels, the gas increased by 14 parts per million in 55 years, occurring about once every 7,000 years. In contrast, at today’s rates, that same magnitude of increase takes only 5 to 6 years. The study also suggests that past periods of natural carbon dioxide rise were accompanied by strengthening westerly winds, which led to a rapid release of CO2 from the Southern Ocean. With predictions of the westerlies strengthening in the future due to climate change, the capacity of the Southern Ocean to absorb human-generated CO2 may be reduced, exacerbating the current climate crisis.
The Southern Ocean plays a crucial role in absorbing carbon dioxide emissions, offsetting the impact of human activities on the climate. However, as southerly winds in the region strengthen, its ability to take up CO2 may be compromised. The study underscores the need to understand and address these climate dynamics to mitigate the effects of rising greenhouse gas emissions. By examining past natural carbon dioxide rises and their impact on the climate system, researchers can better prepare for the future and develop strategies to combat climate change effectively.
Overall, the research provides valuable insights into the historical patterns of carbon dioxide levels and their relationship to climate change events. By comparing past CO2 rises to the current unprecedented rates driven by human activities, scientists can better understand the potential consequences and develop strategies to mitigate the impacts of climate change. The study highlights the importance of studying Earth’s past climate variations in preparing for a sustainable future and underscores the urgent need for global action to address the current climate crisis.
