Ms. TIERNEY. Mr. Burr, would it be worthwhile to also provide context in that response that shows the percentage contribution of total greenhouse gases worldwide that comes from the United States? I believe it is about a quarter. I offer that as context for understanding the order of magnitude of the U.S. contribution to the problem.

[The following information was received for the record:]

The United States accounts for approximately 20 to 25 percent of anthropogenic (man-made) emissions of greenhouse gases, including about 23 percent of carbon dioxide emissions, 8 percent of methane emissions, and about 10 percent of nitrous oxide emissions. The U.S. share of emissions of perfluorocarbons and hydrofluorocarbons is unknown, but probably greater than half of world emissions. The estimates of U.S. and world carbon dioxide emissions are much more reliable than the estimates for the other gases.

Mr. BURR. Let me ask you a question, and I will go to Mr. Hunker. What is our economy as it relates to the participants, size of the economy as it relates to the participants in the convention?

Mr. HUNKER. I don't have those figures on the tips of my finger, but we will be happy to provide them for the record.

[The following information was received for the record:]

As of 1993, we estimate that U.S. Gross Domestic Product (GDP) is about 25 percent of the combined output of countries that have accepted or ratified the convention. A precise figure cannot be calculated because current GDP data for many of the developing countries participants are not available. For purposes of comparison, it is currently estimated that the United States is about 22 percent of world output. From the Handbook of International Statistics, a public document published by the Central Intelligence Agency, the purchasing power parity Gross Domestic Product (GDP) of key participants for 1993 (the latest year available) is :