What is the role of multiyear ice in overall global sea-ice losses? What is the status of this ice today? (Check some websites such as that of the National Snow and Ice Data Center.) What are the main...

What is the role of multiyear ice in overall global sea-ice losses? What is the status of this ice today? (Check some websites such as that of the National Snow and Ice Data Center.)

What are the main sources of carbon dioxide? What are the main sources of atmospheric methane? Why is methane considered to be a more potent greenhouse gas than CO2?