1. Land use for agriculture is going down in the US [1], as with most developed countries. Factory farming is more intensive per acre, leading to fewer. Likewis

1. Land use for agriculture is going down in the US [1], as with most developed countries. Factory farming is more intensive per acre, leading to fewer. Likewise forests in Europe are expanding [2]. Industrialized agriculture leads to less land cultivated because of its greater production per unit of land. Much of the land used for agriculture today was deforested over 70 years ago. 2. NASA puts the estimate at 300-1000 years [3], but it looks like this includes carbon sequestration as one of the decay methods not decay in the atmosphere like methane. Absent sequestration, carbon dioxide lasts a lot longer. 3 & 4. While methane has greater short term effect, the total amount of methane being released is orders of magnitude less. About 2.5 ppm of carbon dioxide is added each year, as compared to methane's 5-7 ppb added each year. Note the difference in units, parts per million versus parts per billion. Sure it's 25x greater impact, but it's emitted 500x less and decays 30-100x faster. That's why methane's contribution to thermal imbalance is relatively static while carbon dioxide's is increasing [4]. Carbon dioxide is overwhelmingly the cause of climate change. 1. https://www.ers.usda.gov/amber-waves/2017/december/a-primer-on-land-use-in-the-united-states/ https://www.ers.usda.gov/amber-waves/2017/december/a-primer-... 2. https://www.weforum.org/agenda/2019/07/forest-europe-environment/ https://www.weforum.org/agenda/2019/07/forest-europe-environ... 3. https://climate.nasa.gov/news/2915/the-atmosphere-getting-a-handle-on-carbon-dioxide/ https://climate.nasa.gov/news/2915/the-atmosphere-getting-a-... 4. https://www.climate.gov/news-features/understanding-climate/climate-change-annual-greenhouse-gas-index https://www.climate.gov/news-features/understanding-climate/...