Generally, as places become higher income, two forces are at work. First, the relative returns to non-agricultural work increase — so, people move from farms to cities into manufacturing, the service sector, etc. This reduces demand for land. Second, there is often an intensification in technology where farming gets more productive, taking some marginal lands out of production.
"Most evidence for this comes from places which offer a reasonable way of measuring productivity — for many jobs, its difficult to do that on a daily basis. These impacts come to 2% to 7% of a reduction of labour productivity, even at modest pollution levels. Thats a big deal."
The adoption of green subsidies could also make fossil fuel producers rationally aware that in the future, they could face much more competition — anticipating this, its in their interest to sell more today. This will speed up emissions. Cumulative emissions over many years might be lowered with the green subsidy — but even so, the acceleration of emissions in the short term has detrimental consequences, which reflects the ‘green paradox.