claim: In April the extent of Arctic sea ice was back to where it was in April 13 years ago
evidence: In 2010, 9.14 gigatonnes of carbon (GtC, equivalent to 33.5 gigatonnes of CO 2 or about 4.3 ppm in Earth's atmosphere) were released from fossil fuels and cement production worldwide, compared to 6.15 GtC in 1990.