crunchは「（クッキーなど）をバリバリ、ボリボリ食べる、かみ砕く」というのが元々の意味ですが（「ガリガリくん」というアイスをうちの子どもがよく食べています）、転じて経済などでは「（財政などの）危機、財政逼迫」（cf. credit crunch、oil crunch）という意味で使われます。
またthe crunchと定冠詞をともなうと、「危機、土壇場」という意味にもなります。when it comes to the crunch...（「いざというときには」）は定番の構文です。
As Japan shuts down nuclear power, emissions rise
TOKYO (AP) -- The Fukushima crisis is eroding years of Japanese efforts to reduce greenhouse gas emissions blamed for global warming, as power plants running on oil and natural gas fill the electricity gap left by now-shuttered nuclear reactors.
Before last year's devastating tsunami triggered meltdowns at the Fukushima Dai-ichi plant, Japan had planned to meet its carbon emissions reduction targets on the assumption that it would rely on nuclear power, long considered a steady, low-emissions source of energy.
But now it's unclear to what extent nuclear energy will even be part of the electricity mix.
Japan will be free of atomic power for the first time since 1966 on Saturday, when the last of its 50 usable reactors is switched off for regular inspections. The central government would like to restart them at some point, but it is running into strong opposition from local citizens and governments.
With the loss of nuclear energy, the Ministry of Environment projects that Japan will produce about 15 percent more greenhouse gas emissions this fiscal year than it did in 1990, the baseline year for measuring progress in reducing emissions. In fiscal 2010, Japan's actual emissions were close to 1990 levels. It also raises doubts about whether it will be able to meet a pledge made in Copenhagen in 2009 to slash emissions by 25 percent from 1990 levels by 2020.
For years, nuclear power was a pillar in Japan's energy and climate policies. Until the Fukushima disaster last year, it accounted for about a third of Japan's power generation, and Tokyo had planned to expand that to half by 2030.
Now Prime Minister Yoshihiko Noda has pledged to reduce reliance on nuclear power, although his government is eager to restart some reactors to meet a looming power crunch during the hot summer months.
"The big open question is whether and when the nuclear plants will come back on line, and what that implies for Japan's long-term emissions trajectory," said Elliot Diringer, executive vice president at the Center for Climate and Energy Solutions, formerly the Pew Center on Global Climate Change, in Arlington, Virginia.
"If nuclear will no longer be a part of the energy mix, Japan is going to have a much tougher time reducing emissions," he said.