What is a Carbon tax?
Fossil fuels like coal, natural gas, oil and aviation fuel contain carbon atoms in them. When they are burnt, these carbon atoms react with oxygen and convert into mostly carbon dioxide and carbon monoxide. These gases enter atmosphere and causes various climatic change, for instance global warming.
Non-fossil fuels like biofuel, biogas and other sources of energy viz. nuclear energy, solar energy and hydropower don't contain carbon atoms. So, when they are burnt, carbon dioxide gas is not emitted; therefore, environment remains unharmed.
To meet the cost of global warming and other consequences of emission of carbon dioxide, a tax is imposed on emission of carbon dioxide, which is carbon tax. This tax, usually imposed directly on fuel, however can be taken in other ways, such as a tax on ticket in case of public transports.

Why tax Aviation sector?
Airlines contribute to 2.5% of total carbon dioxide emissions as of 2008. Scientists fear that this will cross 16% by 2050. As goes the popular belief, if somebody does anything wrong, he's to pay for it. So, when somebody emits carbon dioxide which harms the environment, he has a responsibility of making it up to the rest of the world. It's a person’s responsibility. Keeping this fact in mind, it's high time aviation tax is imposed if it's not done yet and this money can utilized for global war on global warming or other severe climatic changes.

Last century, temperature of the earth witnessed an increase by 0. 74 degree Celsius and this century, the world might witness yet another increase by 1.1 to 6.4 degree Celsius, according to IPCC Climatic model. If global temperature increases by a few degrees, countries like Bangladesh and the Maldives might submerge under the water.
So, it's needed to carry out anti-global warming activities on a mass scale, for instance, afforestation, public awareness building programs and research for environmental technology and for all those, what do we need? Money. Again, we need to decrease annual carbon dioxide emission of airliners. How do we do that?
Simple- taxing the aviation sector for emission of carbon dioxide.

Why airline passengers?
In the context of world's financial situation, it'd be very unwise to impose the tax on airline companies. Again, if airline companies have to pay an extra tax, they'd ultimately increase the ticket price and it'd be the buyer who'd have to pay the burden of the tax and more importantly, at different rates in different airlines.
So, it's wise to impose the tax directly on the airline passengers. Passengers are already poor...How would they pay for it?
If you have this question, it's suggested you read below.

How does it work?
Those should pay more who contribute more to global warming. Following is an approximate statistics showing carbon emission on an airline trip from Washington to Paris by different class of passengers:

Regular Class- 2153 lbs
Economic Class- 4366 lbs
Business Class- 6998 lbs

We see that an economic class passenger emits about 2 times more carbon than that of a regular passenger whereas a passenger of business class emits about 3.25 times more carbon.
Considering the carbon emission and the capacity of the passengers to pay, the tax in percentage can be imposed as below:

Regular Class- 1.5%
Economic Class- 2.5%
Business Class- 5%

That way, it’s easy for every passenger to bear the burden of the tax. For instance, if airfare of regular class from London to Moscow is $250 and that of economic and business class is $350 and $500 respectively, then the three classes of passengers will have to pay a tax of $3.75, $8.75 and $25 respectively. It’s not hard for either class of the passenger; therefore, it doesn’t have a negative impact on the airline industry. If airline passengers can buy airport novels for $10, it would not hurt them to pay $3.75 to recompense for what they are doing to the environment. On the other hand, it isn’t much of a burden to the other two classes also, as these two classes consist mainly of wealthy passengers. They have cheaper options, still they are opting for the expensive choice, with double or triple times more space than that of the regular passengers. This way, in a regular airplane, a tax of about $1300 would be obtained from a flight and if there are 10 flights a day, annual tax from only that plane would be about $5 million.

The VAT Theory
If Carbon tax is imposed on aviation fuel, airliners can get fuel from other countries where carbon tax is not imposed. And to prevent it, a bill has to be passed in a global house. And the UN, however, doesn't appear to Herculean enough to do such a task.
So, what we do is simple: we impose the tax on the ticket price of the passengers just like VAT. It will be received from the same counter where a passenger buys his/her ticket.

What do we do with the money?
There’s no such thing as easy as spending money. However, utilizing them in a way that would actually help the total scenario needs critical thinking. If the government spends money in green-tech research centers which takes interest in inventing environment friendly airplanes like Boeing-787, which runs on biofuel, then number of such projects would increase, ultimately causing an increase in the number of such airplanes. But why would airline companies buy it?
In this context, what can be done is subsidizing biofuel or other green-tech energy sources if found. If the price of these energy sources can be brought down below regular aviation fuel, it'd ultimately prompt the airline companies to buy green-tech airplanes to maximize their profit through the use of cheaper fuel and thus, annual carbon dioxide emission would come down.
Besides, the money can also be utlilized in traditional environmental projects such as public awareness building program and afforestation programs. This way, environmental balance can be restored.

Stances of Political Personalities
US Senators Christopher Dodd promoted carbon tax in his recently ended election campaigns. Same goes for congressmen Pete Stark and Jim McDermott. They advocated for "Save Our Climate Act” which would impose a tax of $10 per ton of coal. But, the model here, however suggests that the tax be imposed on the ticket price of the passengers rather than levying aviation fuel. Even if the tax is imposed on aviation fuel, the airline companies would ultimately increase their ticket fare and it'd be airline passengers who'd have to pay the burden of this tax. It'd turn out to be some sort of indirect tax and the indirect tax might not be uniform, unlike the model described in this article.
A top EU official on climatic change, Jos Delbeke was quoted last year having said emissions trading is the second best alternative to carbon tax. Emissions trading is also regarded as an alternative to carbon tax, but carbon tax is much more simple and feasible. Other supporters of carbon tax include Bill Clinton and Al Gore.

Lastly...
The overall process of carbon tax is simple, transparent and easily understandable. Because of these features, it's more likely to be popular among public rather than it’s other alternatives, for instance emissions trading. It is also less vulnerable to corruption, as the whole procedure is transparent and can be easily monitored. Therefore, it's possible to implement this even in a third world country affected with corruption.

We have only one earth to live on and one planet to care for. Airline passengers should pay for the harm they are causing to the environment and the proper way to do that is to pay a carbon emissions tax. In the present situation of the earth, with global warming and other climatic changes on the rise, we don’t have the luxury to wait anymore. A rise of global temperature by a few degrees- countries like Bangladesh and the Maldives are past. It’s about time that carbon tax is imposed on airline passengers and utilized in a proper way to neutralize the effect of global warming. Our only abode will then be greener, safer and healthier-not only for the future generation but also for the current inhabitants of it.