Background Paragraph: Carbon dioxide is the most significant long-lived greenhouse gas in Earth's atmosphere. Since the Industrial Revolution anthropogenic emissions – primarily from use of fossil fuels and deforestation – have rapidly increased its concentration in the atmosphere, leading to global warming.  Carbon dioxide also causes ocean acidification because it dissolves in water to form carbonic acid. 
Story: Ben and Andy researched significant greenhouse gasses in Earth's atmosphere. Andy researched more about carbon dioxide, while Ben researched methane gas.
Which researcher studied another significant long-lived greenhouse gas in Earth's atmosphere? Which researcher studied less about anthropogenic emissions? Which researcher studied less about deforestation? Which researcher studied less about ocean acidification? Which researcher studied less about the use of fossil fuels? Which researcher studied more about anthropogenic emissions? Which researcher studied more about deforestation? Which researcher studied more about ocean acidification? Which researcher studied more about the use of fossil fuels? Which researcher studied the most significant long-lived greenhouse gas in Earth's atmosphere?