An analyst warned that the Group of 7 nations need to be prepared for a complete shut down of the Russian gas pipes.
A shutdown of gas is what the G-7 have to prepare for. A cutback on oil can be dealt with by the G-7. Jeffrey Schott, a senior fellow at the Peterson Institute for International Economics, told CNBC on Monday that gas could be shut off and that would have consequences.
Russia has cut back on gas flowing to Germany and through Ukraine, so shutting down the pipes is not out of the realm of possibility. He said in an email that Russia sells some gas to Europe but not a lot.
He said that the cut-off of Russian supplies would cause gas rationing. Russian supplies would be partially offset by increased imports of liquified natural gas, fuel-switching to coal, and other measures.
Over the last few weeks, Russia's state-backed energy supplier has reduced its gas flows to Europe. Germany, Italy, Austria, and the Netherlands all indicated they could return to coal.
The leaders of the G-7 wealthiest nations met in Germany for a summit.
Europe is facing a very tight situation as global pressure continues to pile on Russia over its assault on Ukraine.
The players are playing for time. Putin may act to cut off gas to Europe if there is a hostile attitude towards Russia. He said that he sees that coming sooner than later.
European leaders are worried about the possibility of a total shut down of Russian gas supplies.
Germany has declared that it is moving to the so-called "alert level" of its emergency gas plan because of reduced Russian flows.
Robert Habeck, Germany's Economy Minister, said on Thursday that Germany would move to stage two of its three-stage plan.
The EU gets 40% of its gas from Russian lines and is trying to reduce its dependence on Russian gas in response to the Kremlin's attack on Ukraine.
The action taken to stop buying Russian gold is one small step in the right direction.
Germany sought to maintain strong energy ties with Moscow.
European growth would be in danger if there was a cut-off of gas before the European gas reserves were filled. It remains to be seen if Putin will follow through with his threat, as he put his cards on the table.
The G-7 leaders are expected to impose a ban on Russian gold imports in order to deny the Kremlin revenue it needs to fund the war against Ukraine.
The action taken to stop buying Russian gold is a small step in the right direction.
Creon Butler, director of economy and finance program at Chatham House, told CNBC on Monday that the restrictions on Russian gold exports is worth billions of dollars to Moscow.
He said that it wasn't something that would get a buy-in from all the nations in the G-7.
The problem is illustrated by that. There are a number of concrete things they can do, but I don't believe they can pull off a unified G-7 approach.
CNBC contributors contributed to the report.