claim: Despite the logarithmic relationship between CO2 and surface temperatures, atmospheric CO2 levels are rising so fast that unless we dramatically decrease our emissions, global warming will accelerate over the 21st Century.
evidence: A month before formal AR5 publication, a leaked draft of the report noted that "Models do not generally reproduce the observed reduction in surface warming trend over the last 10–15 years", but lacked clear explanations, and attracted wide media coverage.