Scientists ran simulations of climate influences and each on revealed global warming occurring over the last 10,000 years.
Professor Liu explained that we know atmospheric carbon dioxide rose by 20 parts per million before the 20th century, and the massive ice sheet of the Last Glacial Maximum has been retreating.
These physical changes suggest that, globally, the annual mean global temperature should have continued to warm, even as regions of the world experienced cooling, such as during the Little Ice Age in Europe between the 16th and 19th centuries.
