But many people including some reputable scientists remain unconvinced that human activity is to blame for global warming. A recent Pew Research Center survey found that only 47 percent of Americans believe the earth is warming due to human activity.

Nonetheless, many business travelers and their employers are increasingly concerned about the environment. At the International Monetary Fund (IMF), Caro Cook is implementing an environmental awareness plan. Although the IMF has environmental programs in other parts of the organization, the chief of the IMF transportation section, says in the travel area, we are just really beginning to understand the carbon emissions piece.

Carbon emissions are at the heart of the global warming controversy. An air traveler generates approximately 2,500 pounds of carbon dioxide emissions on a round-trip from New York to London. By contrast, the average automobile produces 10,000 pounds of carbon dioxide annually. To help corporations assess their carbon liability the Association of Corporate Travel Executives (ACTE) has added a carbon emissions counter to its website.

Counting carbon emissions is fine, but what can you do to mitigate your impact on greenhouse gas emissions without forfeiting travel An increasing number of travel companies now offer carbon offsets” and other programs aimed at neutralizing your impact on the environment. British Airways, Expedia, and Travelocity are among a handful of travel companies to implement a carbon offset program:

Through a company called Climate Care, British Airways allows passengers to calculate carbon emissions based on trip mileage and offset those emissions with a donation to Climate Care which operates numerous sustainable energy programs around the world. The approximate cost of an offset for a New York to London round trip is $17.

Expedia offers a similar offset program through a company called TerraPass. Expedia customers have offset almost 14,000 tons of carbon dioxide or more than 65 million passenger miles to date according to spokesperson Katie Deines.

Travelocity’s GoZero program additionally plants trees on request. Travelocity is planting 4,000 trees currently according to Jeffery Glueck, chief marketing officer. Each tree absorbs 1.3 tons of carbon dioxide in its life.

Silverjet, the new discount all business class airline flying between New York and London, has taken its program one step further and made carbon offsets mandatory by including them in the price of a ticket.

Not to be outdone by anyone, Richard Branson has also initiated his own program to channel $3 billion in profits from his Virgin empire over the next 10 years to research renewable energy resources.rnrnAll of these ventures are steps in the right direction, but I wonder if carbon offsetting will disappear within the next few years with the proliferation of taxes or fees like the recently imposed “”green tax”” in United Kingdom on all flights departing British airports. The tax is 20 British pounds (approximately $40) for economy class and 40 British pounds ($80) for business/first class for each departure.

The European Union has also proposed a plan to cap carbon emissions at previous levels beginning in 2011. In an elaborate scheme, every airline operating in European air space would receive an emissions cap based on a subset of previous emission levels. Airlines seeking expansion would need to purchase additional emissions allowances from the government or other companies that are not planning to use their budgeted quota of emissions. Like the carbon offsets, the revenues from this tax would be used for environmental projects.rnrnThe program already has a slew of critics who believe the tax will raise airline ticket prices anywhere from $9 to $80 and that there is no accountability for spending the funds on their intended use.

There are also those who question the wisdom of taxing aviation when it is a far more efficient method of travel than automobile. Aviation emissions have declined 70% in the past 40 years, according to the International Air Transport Association (IATA) while carbon emissions from road vehicles, power plants and two-stroke engines such as those in lawnmowers and snow blower comprise the lion’s share of greenhouse gases.

Although air travel is likely to grow over the next decade, especially in China and India, even if air travel rises 50% it will only comprise 3% of all carbon emissions. And IATA expects the industry to be 20% more fuel efficient in the next decade with the arrival of next generation aircraft.

Although every little bit of conservation helps, it does seem baffling why so much attention is focused on air travel when it only comprises a few percent of the human induced greenhouse gases.

So I guess that brings us back to the original question: fly or stay home? I can’t answer that question for you; it really depends on your convictions and beliefs. But personally, I will probably fly a little less and pay a little more in the short term, and hope that we’re all doing enough to protect the planet. rnrn rnrnrnJohn Welford recently posed a provocative question to hundreds of colleagues on an online list-serv. Now that the world has become aware of the growing crisis of global warming, is it ethical for organizations to hold large international conferences to which thousands of people will travel by air”” asked Welford, a freelance editor based in the United Kingdom.

Welford asked his peers if it made more sense to shrink the size of a conference so most attendees could participate via podcast, or set up an interactive remote Web session sparing the environment from damaging greenhouse gases emitted by airplanes.rnrnNot surprisingly, Welfords idea was met with stiff resistance by his American counterparts, but I must admit I felt conflicted. Certainly being there is more engaging than sitting in front of the computer screen. I like to wander the exhibit hall or share a brisk discussion over a beer with my contemporaries, but is the value of that face time enough to overcome any adverse environmental impact my voyage may have caused?

The United Nations Intergovernmental Panel on Climate Change recently released a report stating that Global atmospheric concentrations of carbon dioxide, methane and nitrous oxide have increased markedly as a result of human activities since 1750 and now far exceed pre-industrial values and increases in carbon dioxide concentration are due primarily to fossil fuel use and land-use change.