Exxon has announced $17 billion of investment in its low carbon business, which includes carbon capture, and has argued that greenhouse gas emissions are the problem causing climate change, not the fossil fuels themselves. He said he believed oil and gas would play an "important role" in the world through 2050, but declined to provide an estimate for demand levels. As part of Exxon's low carbon strategy, it announced in July a $4.9 billion acquisition of Denbury and its 1,300-mile (2,100-kilometer) carbon dioxide pipeline network, which will be linked to offshore blocks in the Gulf of Mexico where Exxon plans to bury carbon. Exxon has so far convinced the largest ammonia maker in the United States, an industrial gas company and a large steel company to ink long-term contracts for carbon reduction services that would cover around 5 million tons of carbon dioxide per year. Currently, energy and industry produce about 37 billion tons of CO2 per year globally.