The Intergovernmental Panel on Climate Change (IPCC) estimates that in parts of Asia, climate change could result in declines in agricultural (not including animal) output by between 2.5–10% by the 2020’s and by 5–30% by the 2050’s compared to 1990 levels (without CO2 fertilization effects). This figure shows longer-term estimates of the crop yield decreases in India, Indonesia, Malaysia, Philippines, Thailand, and Vietnam. The declines are lower if carbon fertilization — a process whereby elevated levels of carbon dioxide in the atmosphere may lead to an increase in crop productivity — is taken into account. Whether the carbon fertilization effect will materialize is uncertain, though it is unlikely to fully make up for crop yield decreases, as shown here.