From his convalescent bed, Fidel Castro has summoned the energy to spit in George W. Bush's direction, decrying U.S. military expenditures and -- is he not tuned in to bien-pensant fashion? -- flagellating the president for resisting a German proposal on global warming. Meanwhile, in Caracas, Castro's acolyte, Hugo Chavez, is proving himself a faithful pupil of the old master by shutting down Venezuela's only opposition television station. But I digress.

Next week, the leaders of the Group of Eight will meet in Heiligendamm, Germany, to discuss the major challenges facing the world. The industrial giants will discuss poverty in the Third World, hedge-fund transparency and energy issues. But the chief topic and agenda item will be global warming. Germany's chancellor, Angela Merkel, will propose to stop the rate of increase in world temperatures by reducing global greenhouse gas emissions to 50 percent below 1990 levels by 2050.

Quite a tall order. But leaving that aside, it's astounding that the leaders of the world's largest democracies (with the exception of Russia, of course) have persuaded themselves that climate change is the chief threat to peace and security in the world while every day brings us closer to a nuclear-armed North Korea and Iran. One of the world's two largest proliferators, Russia, is an esteemed member of the G8 club. The other menace to peace is China, which has paid no price for its reckless support of Kim Jong Il and the mullahs of Iran.

China is arguably the godfather of nuclear proliferation, having supplied Pakistan with warhead designs, nuclear test data and plutonium technology that permitted the Pakistanis to go nuclear in the 1990s. As Gordon Chang reports in Commentary magazine, what China shared with Pakistan the Pakistanis soon shared with North Korea (among others), thanks to the busy career of Dr. Abdul Qadeer Khan. (India, by contrast, has kept its nuclear know-how to itself.)

While the U.S. has been attempting through carrots and sticks to cajole and threaten North Korea into abandoning its nuclear program, the Chinese, whose influence over the North Koreans is superior to anyone's, have done little to discourage their client. If China were to open its border with North Korea, the latter would rapidly become depopulated -- which might represent a solution both simple and humanitarian.

But while China has occasionally expressed irritation with North Korea, it has also coddled and protected it. Beijing has run diplomatic interference for Pyongyang by watering down Security Council resolutions sponsored by the United States. China has also dragged out the so-called "six party talks," giving North Korea the time it needs to perfect a nuclear weapons program.

As for the Iranian nuclear program, both China and Russia have taken a tolerant if not downright encouraging approach to Iran's pursuit of nuclear weapons. China has reportedly shared beryllium, used to trigger nuclear weapons, with Iran, and Chinese nuclear technicians have been known to be in Iran. Both Russia and China have resisted U.S. and some European efforts to impose serious sanctions on Tehran. Chang writes:

"When the United States did finally manage to put Iran on the [Security] Council's agenda, Russia and China . . . refused to consider sanctions, which meant that the July 2006 resolution contained no enforcement measures. Then, when it came time to respond to Tehran's continued intransigence, the pair, over two long months, diluted proposal after proposal until the sanctions that eventually emerged last December . . . were essentially meaningless."

Russia is building a reactor for Iran -- all for peaceful nuclear power, all parties insist -- though why a nation with one of the largest deposits of oil and gas would require nuclear energy goes unasked. "We think that the people of Iran should have access to modern technologies, including nuclear ones," Vladimir Putin explained.

The Iranian regime is now illegally holding five U.S. citizens, arming the worst terrorists on the globe and supplying the insurgents in Iraq with weaponry with which to kill Americans -- all while its febrile president talks of the return of the 12th imam. North Korea starves and enslaves its people and trades drugs and counterfeit U.S. dollars. Both are on the verge of becoming armed with nuclear weapons. But neither is as important as global warming?