evidence: Measurements from the pre-industrial revolution through to today match that prediction extremely well. Since the 1880s we have increased CO2 by about 50%, and temperatures have increased by 1.1°C. [...] What’s more, they showed that present levels of CO2 and methane in the atmosphere are above anything seen in the past 420,000 years. [...] Together Antarctic ice cores show us that the concentration of CO2 was stable over the last millennium until the early 19th century. It then started to rise, and its concentration is now nearly 50% higher than it was before the industrial revolution.