The trajectories for emissions of carbon dioxide as the world’s industrial and industrializing countries boost coal burning are clearly going to be tough to turn around, whether through caps on emissions or efforts to improve non-polluting energy technologies. And big hurdles remain before there will be any large-scale capturing of carbon dioxide to pump it underground or elsewhere for safekeeping.

That’s why a growing number of scientists, including Nobel Prize winners and Ralph J. Cicerone, the president of the National Academy of Sciences, have pushed for intensified study of ways to artificially nudge the planet’s thermostat downward — at the very least as a “Plan C” should warming kick into high gear. We’ve touched on such technologies for years, including a story in our Energy Challenge series by William J. Broad in 2006 exploring the growing support for examining earth-cooling options ranging from mirrors in space to adding a sulfate veil to the atmosphere. But will they ever come to pass?

A question for climate skeptics: I presume you agree there’s at least a chance you could be wrong, just as you assert those pointing to a clearcut climate apocalypse have little basis for their claims. On that front, I’d be curious to know what you’d propose as a backup plan if the climate’s sensitivity to CO2 turns out to be higher than you think?

Seeing an End to the Good Times (Such as They Were)

The Obama people seem to have persuaded themselves they can go on the attack, but in the right way. They can be tough and keep their virginity, too. But there are more than five long months between now and the convention.

Unless they consciously reject conventional politics, the accusations will build on each other. The BlackBerries will buzz. The passions will rise. The Obama forces will see hints of Clinton corruption all around, and they’ll accuse and accuse again. The war will begin to take control, and once you’re halfway through you can’t suddenly surrender because it’s become too rough.

And the Clinton people will draw them every step of the way. Clinton can’t compete on personality, but a knife fight is her only real hope of victory. She has nothing to lose because she never promised to purify America. Her campaign doesn’t depend on the enthusiasm of upper-middle-class goo-goos.

Inner time is linked to activity. When we do nothing, and nothing happens around us, we’re unable to track time. In 1962, Michel Siffre, a French geologist, confined himself in a dark cave and discovered that he lost his sense of time. Emerging after what he had calculated were 45 days, he was startled to find that a full 61 days had elapsed.

The perceived lack of time becomes real: We are not stressed because we have no time, but rather, we have no time because we are stressed.

Studies have shown the alarming extent of the problem: office workers are no longer able to stay focused on one specific task for more than about three minutes, which means a great loss of productivity. The misguided notion that time is money actually costs us money.

And it costs us time. People in industrial nations lose more years from disability and premature death due to stress-related illnesses like heart disease and depression than from other ailments. In scrambling to use time to the hilt, we wind up with less of it.

Clinton demanded that Obama do more than "denounce" Farrakhan's endorsement. Obama responded that he didn't see the difference between denouncing and rejecting but said: "If the word 'reject' Senator Clinton feels is stronger than the word 'denounce,' then I'm happy to concede the point, and I would reject and denounce."

Thus we have the Farrakhan litmus test, a sort of oral examination often administered to black political candidates. It's one of many tests Obama can expect to face in the coming weeks.

Whether Obama passed or failed the Farrakhan test might depend on where you stand on Obama's candidacy. But the exchange regarding the controversial Nation of Islam leader probably did Hillary Clinton some good, given Farrakhan's radioactivity in many parts of the country.

Which raises the question: Where was Hillary Clinton when her husband, former president Bill Clinton, made nice with Louis Farrakhan?

What? You didn't know?

In a May 2005 interview with the black weekly newspaper the New York Amsterdam News, the former president said that he supported the efforts of Louis Farrakhan and the Revs. Al Sharpton and Jesse Jackson to organize a Million More March in the nation's capital that fall.  ...

Bill Clinton, sitting with the Amsterdam News and enjoying his first full day in the office since his second operation, was good to go with Farrakhan's leadership of the Million More March -- a fact he was willing to share with . . . a black audience.

And, pray tell, what was Hillary Clinton doing then?

She was, as she is now, a U.S. senator from New York.

Did Hillary get on Bill's case, too?

Hush my mouth! Now I've quit reporting and gone to meddling.

The costs of leaving Iraq unstable would be high. Jihadists everywhere would be emboldened. I have met many Gulf leaders and know that their deep fear is that a precipitate U.S. withdrawal would gravely jeopardize their security.

A hurried withdrawal from Iraq would cause the leaders of many countries to conclude that the American people cannot tolerate the nearly 4,000 casualties they have suffered in Iraq and that in a protracted asymmetrical war the U.S. government will not have its people's support to bear the pain that is necessary to prevail.  ...

An additional concern is that a hasty U.S. withdrawal would leave Iran to become more of a power in the Gulf.

Iran is Shiite, not Sunni. Shiites are the largest group in Iraq, too. The schism between Shiites and Sunnis goes back more than a millennium to the very earliest years of Islam. The divide between Arabs and Persians is even more ancient.

Every Gulf state has a significant Shiite minority but is ruled by Sunni leaders. A dominant Iran with no regional counterweight would shift the balance of power between Sunnis and Shiites in the Middle East, changing the internal and external politics of the region. To survive, Iran's neighbors would adjust their positions.  ...

A few years ago, the Taliban in Afghanistan and Saddam Hussein's Iraq were a check on Iran. The Taliban is again gathering strength, and a Taliban victory in Afghanistan or Pakistan would reverberate throughout the Muslim world. It would influence the grand debate among Muslims on the future of Islam. A severely retrograde form of Islam would be seen to have defeated modernity twice: first the Soviet Union, then the United States. There would be profound consequences, especially in the campaign against terrorism.

Singapore supported the United States in Iraq and Afghanistan and continues to do so. My country has deployed amphibious support ships in the Gulf as well as transport aircraft and refueling tankers to assist U.S. forces. We are also helping with reconstruction efforts in Afghanistan. We have placed these symbolic chips on the table because we realize that the global stakes are extremely high.

Janice Crouse of Concerned Women for America said she asked him about the nearly 40 percent of women in America who bear children out of wedlock and how he would address that problem.

On the proposed Law of the Seas Treaty that President Bush supports and that conservatives generally oppose, Mr. McCain split the difference, saying the treaty as proposed surrenders "way too much" of America's sovereignty, but it needs to be renegotiated because international law needs "coherence" in this area.

He has a mighty big carbon footprint.

Al Gore's opulent lifestyle and his virtuous plea to save the planet from global warming don't mesh, according to the Competitive Enterprise Institute (CEI), which announced plans yesterday for a new national advertising campaign to showcase the contrast before the American public.

My preference would be for dollar depreciation to reduce the current account deficit and slow the accumulation of dollar assets abroad. That process has recently begun. Exports of goods and services in December were up $2.2 billion from November while imports were down by the same amount, more than accounting for the annual December to December improvement in the deficit of only $1.5 billion. Hopefully, that reduction in the trade deficit will continue, but chances are the recent appreciation in the dollar from its lows will slow or halt that improvement.

The level of the dollar is important for trade. But for foreign investors, the level of the dollar is not as important as its expected future movement.

They want to get into U.S. assets when the dollar is cheap and get out when the dollar is dear. The more the dollar depreciates, the sooner it will be expected to reverse, and the sooner foreign investors will resume their participation in the most dynamic, creative economy in the world.

A premature strengthening of the dollar would slow needed trade adjustment and neutralize foreign trade as a source of domestic demand as we try to avoid a severe recession. Once again, Lord make our dollar strong, but not just yet.

Israel and Western democracies must treat the terrorists' mortal challenge as a war for survival, not as a series of skirmishes. And in war, you must fight to win, by all traditional means.

With all the talk about how Mr. McCain needs to unify his party, lost has been the question of whether some people will let him. Washington Republicans know he's their best shot at retaining the White House. Yet many remain ambivalent about him -- not because they question his conservatism, but out of resentment that he may get in the way of their earmarks.

This has resulted in a behind-the-scenes brawl, as spend-happy Republicans resist efforts by wiser heads to fall in behind Mr. McCain's anti-earmark message. At best, the spenders risk an embarrassing pummeling by their own nominee that could hurt them in their own re-election campaigns. At worst, they could undercut one of Mr. McCain's more persuasive messages.

They shouldn't count on Mr. McCain cutting them slack. He's always reveled in publicly humiliating pork-barrelers, including those in his party, and seems gleeful at the prospect of using his new podium to continue his crusade. He has no reason to back down now. Unorthodox as he's been on some conservative issues, on earmarks Mr. McCain has the full backing of an American public.  ...

The pork-barrelers also risk diluting one of Mr. McCain's winning messages. Hillary Clinton has a miserable earmark record, which Mr. McCain has used to embarrass her over a funding request for a Woodstock museum. Mr. Obama likes to point to Senate work to increase earmark transparency. But he too has asked for plenty of money and refused to release information about his early earmark requests. Either Democrat will want to neutralize this issue.

The 1856 GOP platform spoke directly of the "twin relics of barbarism, polygamy and slavery." We fought a bloody war to end slavery, and the federal government undertook a decade's long legal enforcement effort to eradicate polygamy among Mormons a few years later, capped by the 1879 Supreme Court case Reynolds vs. the U.S..  To this day, when the government uncovers cases of slavery, it takes vigorous action, including jail time and deportations. Unless we wish to become like Western Europe — colonized, and forced to support, with our tax dollars, laws and practices we find abhorrent — it's time to take similar action when we uncover cases of polygamy.

His carefully crafted economic message of populist irresponsible nonsense was cruelly betrayed by a campaign adviser who discreetly told the Canadian Government that the protectionist propaganda that Mr Obama was peddling on the campaign trail would be safely jettisoned once he got to the White House. On Monday his dubious financial links with a property developer came back to haunt him.

Then the media, having for most of the campaign struck a posture of infatuated awe with Mr Obama, finally got off their knees and started asking serious questions. The senator didn't much like this and called an aggrieved halt at a press conference this week after only eight questions.

The danger, I think, for Mr Obama is that the kitchen sink volley of the last week has revealed a central truth about the Democratic contest: she wants it more. In politics, it's not necessarily the better person who gets the top job, but the one who is really, really desperate for it and willing to go to any lengths to get it.

For Mrs Clinton - and for her momentarily quiet husband - this is it. This is the alpha and omega of their existence; the sacred mission at the heart of their life's journey. They will do anything to get there. Mr Obama has time on his side - at only 46 he will be a leader of the Democratic party for 20 years or more.

In another clever move after this week's primaries, Mrs Clinton showed she perhaps senses this disparity of political hunger when she mooted the idea of a “dream ticket” for the Democrats - she as the presidential candidate, Mr Obama as the vice-president.

It makes perfect sense for her and might, if he thinks really hard about it, suit him. If they win in November, he is the heir apparent when she ultimately steps down. If they lose, he is the immediate successor.

And after another week or two like the last, Mr Obama may finally decide it's better to have Mrs Clinton on his side than have her throwing the plumbing at him.

Weeks of hard work by Iranian emissaries and pro-Iran elements in Iraq were supposed to ensure massive crowds thronging the streets of Baghdad and throwing flowers on the path of the visiting Iranian leader. Instead, no more than a handful of Iraqis turned up for the occasion. The numbers were so low that the state-owned TV channels in Iran decided not to use the footage at all.

Instead, much larger crowds gathered to protest Ahmadinejad's visit. In the Adhamiya district of Baghdad, several thousand poured into the streets with cries of "Iranian aggressor, go home!"

The visit's highlight was supposed to be a pilgrimage to Karbala and Najaf, the "holiest" of Shiite cities in Iraq. There, Ahmadinejad was supposed to become the first Iranian government leader since 1976 to pray at the mausoleums of Imam Hussein and Imam Ali.

In the end, however, the tour was canceled amid reports that Shiite pilgrims, including thousands from Iran, were planning to demonstrate against his presence at the "holy" cities.

A more important reason motivated Ahmadinejad to drop his planned visits to Najaf - his failure to arrange an encounter with the leading ayatollahs of the "holy" city, especially Grand Ayatollah Ali-Muhammad Sistani, the leading Shiite clergyman.  ...

He had already been obliged to cancel a visit to Samarra, where the "Hidden Imam" disappeared in a well on 941 AD. Ahmadinejad had hoped to visit the ruins of the golden-domed Mausoleum of the Two Imams that was bombed by al Qaeda in 2005 and 2006 and announce a plan to rebuild the mausoleum.

The project is of special importance to Ahmadinejad, who claims to be in direct contact with the "Hidden Imam." (Last year he told his Cabinet that the "Hidden Imam" had accompanied him to the United Nations and filled the General Assembly's hall with a green light during his speech.)

But two days of demonstrations against Ahmadinejad's planned visit by the people of Samarra forced him to strike the city off his itinerary.

Nor did Ahmadinejad's presence in Baghdad go as smoothly as he'd hoped. A good part of the Iraqi political elite, including Cabinet ministers and members of the parliament, boycotted functions held in his honor. Tehran has branded the boycotters as "Saddamites and Sunnis in fact, a good number of Shiite politicians, including the leaders of the Fadila (Virtue) Party, also stayed away.

Protest marches against Ahmadinejad weren't limited to predominantly Sunni Arab cities such as Mosul, Kirkuk and Fallujah. Thousands of people also turned out in Shiite-majority Basra, Iraq's second-largest city, to oppose the visit and condemn the Islamic Republic's intervention in domestic Iraqi affairs.

The visit's political side was equally disappointing for Ahmadinejad. He failed to persuade the Iraqi leaders to stop negotiations with America on long-term arrangements ensuring US commitment to new Iraq for several more years. Nor did he succeed in obtaining cast-iron guarantees that new Iraq won't seek to renegotiate aspects of the 1975 Treaty with Iran. (Iraqi President Jalal Talabani told an interviewer last year that the treaty, signed by Saddam Hussein, doesn't reflect the interests of the Iraqi people.)

Ahmadinejad's visit also failed to produce results on such perennial Irano-Iraqi problems as the fate of thousands from both sides who remain missing in action since the 1980-88 war, and plans for reopening the Shatt al-Arab border estuary to allow a revival of maritime transport in that corner of southwestern Iran.

The Iranian visitor failed on another issue close to the heart of Iran's ruling mullahs: the handover of some 4,000 members of the Mujahedin Khalq (People's Combatants)...

Ahmadinejad had come to Iraq to show it was an Iranian playground. He ended up by showing that Iran's influence in Iraq is widely exaggerated.

As Ali Gallagher, a white female (sorry, this identity-politics labeling is contagious) from Texas, told the Washington Post: “A friend of mine, a black man, said to me, ‘My ancestors came to this country in chains; I’m voting for Barack.’ I told him, ‘Well, my sisters came here in chains and on their periods; I’m voting for Hillary.’ ”

When everybody’s a victim, nobody’s a victim. Poor Ms. Gallagher can’t appreciate the distinction between purely metaphorical chains and real ones, or even how offensive it might be to assume blithely that there’s no difference whatsoever.

On the other hand, Barack’s ancestors didn’t come here in chains either: his mother was a white Kansan, so was presumably undergoing menstrual hell with the Gallagher gals, and his dad was a black man a long way away in colonial Kenya. Indeed, Senator Obama would be the first son of a British subject to serve as president since those slaveholding types elected in the early days of the republic. As some aggrieved black activist sniffed snootily on TV, Barack isn’t really an “African-American” — unless by “African-American,” you mean somebody whose parentage is half-American and half-African, and let’s face it, no one would come up with so cockamamie a definition as that.

If it’s Historical Guilt vs. Joe Biden and John Edwards, bet on Historical Guilt, and the Democratic base uniting around Hillary and baying “I Am Woman, Hear Me Roar”. Instead, it’s “I Am Woman, Hear Me Whine About The Unfairness Of It All,” as the Clintonites go nuclear and accuse Obama, the ultimate cool black dude, of “imitating Ken Starr,” the ultimate uptight squaresville honky. Which may be a marginally less ineffective line of attack than Gloria Steinem (now 112 but still fabulously hot) complaining to The New York Observer that way too many Americans want “redemption for racism” but not enough want “redemption for the gynocide.” Which may, in turn, be a marginally less fatal shot in the foot than former Carter-administration honcho Andrew Young’s perplexing boast that Bill Clinton has slept with more black women than Obama.

After news reached Gaza yesterday evening that eight teenagers had been shot dead and many more injured in the library of a Jewish religious school in Jerusalem, thousands of Palestinians took to the streets to celebrate.

Here is the footage of “impoverished” Gazans handing out sweets and candies to passing motorists honking their horns in joy. I strongly suggest you watch it and ask why the footage is not being broadcast on major Western TV networks. (The clip is from Israeli TV news taken from Palestinian TV news.) Might it spoil the sympathy for Palestinians that the BBC, CNN, and others are trying to ram down viewers’ throats all the time?

In mosques throughout Gaza, thousands of residents went to perform the prayers of thanksgiving. There were also similar celebrations on the streets of Tehran last night.

He has the right idea in mind. McCain thinks three vice presidential picks from the recent past were wise: Republican Dick Cheney in 2000 and Democrats Joe Lieberman in 2000 and Al Gore in 1992. They were nationally known political heavyweights who passed the most important test. They were accepted almost instantly as ready to replace the president if necessary. And they had no significant drawbacks.

The list of plausible presidents is short. Mitt Romney, Rudy Giuliani, Fred Thompson, Tom Ridge, and Joe Lieberman qualify. That's about it.

There are a number of popular Republican governors--Charlie Crist of Florida, Tim Pawlenty of Minnesota, Mark Sanford of South Carolina, Haley Barbour of Mississippi--but they fall short of Cheney-Lieberman-Gore stature. It's not their fault, but it's nonetheless true.

Susan Rice says he's not ready for that 3 am phone call. Samantha Power calls Hillary a monster AND says he's bluffing on withdrawing forces from Iraq. Austan Goolsbee says he's bluffing on NAFTA. And now this. He's bluffing on telecom immunity.

The funny thing is that these advisers are all right. Obama's in lala land making promises he can't possibly keep and his advisers are just stating the obvious. Their guy has no experience (not an automatic disqualification for office), he isn't going to pull troops out of Iraq (because that would be crazy), he isn't going to withdraw from NAFTA (also crazy), and he isn't going to let telecom companies go bankrupt because they did their patriotic duty.

If anything, he's surrounded himself with smart people. That's something.

One thought about the Jerusalem massacre: the lack of moral outrage about the fact that the gunman disguised himself as a rabbinical student.

Although the media frequently covers protests by outraged Muslims throwing temper tantrums at any perceived disrespect to their religion, Reuters and other news outlets fail to focus on the transparent hypocrisy when writing about terrorist attacks against Jews and Catholics. Not only do the terrorist sympathizers celebrate attacks against other religions with street-parties, prayers, and sweets, they fail to condemn al Qaeda’s bombing of mosques, which presumably contain an abundant supply of oh so sacred Korans.

According to the most recent Gallup poll, "A record proportion of Americans -- 47% -- say the United States' national defense is not strong enough. Another 41% say the country's defense is about right, while 10% say it is stronger than it needs to be."

...The percentage of Americans who say the U.S. national defense is not strong enough has increased steadily since 2004 and now is at its highest point since Gallup has been asking this question in 1984.

It’s possible the ongoing U.S. engagement in Iraq and Afghanistan is contributing to an ever-larger proportion of Americans desiring a stronger military. Whatever the reasons, the trend over the past four years is striking.

"The failure of the Iraqi state would be a disaster.  It would dishonor the ... men and women who have already died. . . . It would be a betrayal of the promise that we made to the Iraqi people, and it would be hugely destabilizing from a national security perspective." -- Barack Obama to the Christian Science Monitor

The spring before his wife began her White House campaign, former President Bill Clinton earned $700,000 for his foundation by selling stock that he had been given from an Internet search company that was co-founded by a convicted felon and backed by the Chinese government, public records show.