I first caught the travel bug when I moved to China aged 19. Ever since, I've spent every free moment and every spare penny exploring the world, from backpacking through southeast Asia to studying in Australia, the United States and all over Europe - and then later, visiting the friends I've made along the way.

But after almost 200 nations came together last December to finally agree to a climate change plan to limit the rise of the global average temperature to maximum 2 degrees Celsius (3.6 degrees Fahrenheit), I came to a horrible realization: My travel habit is part of the problem we've agreed to fight.

Flying all over the world - to South Africa, the United States, India and Egypt in just the past year - comes with a pretty hefty price tag. And I'm not just talking about my bank balance - I'm talking about the future of our planet.

Flying is an environment killer

Airplanes release more CO2 than any other form of transport

Travel-related activities account for up to 14 percent of worldwide greenhouse gas emissions each year, according to the United Nations Environmental Program.

At this very moment, there are more than 1,500 airplanes crisscrossing world's skies at the same time. You can even watch them on flight tracking websites such as Flightradar 24. The number of planes in the sky can top 10,000 at peak travel times. That's a lot of planes. Incredibly, roughly half a million people are in the sky right now as you read this.

And that's very bad news for our climate. No other means of transport spews more CO2 into the atmosphere than planes. In fact, globally the aviation industry uses 1.5 billion barrels of jet fuel each year. That oil is emitted as carbon dioxide, the key driver of global warming. And there are no regulations controlling how much CO2 airline companies are allowed to produce.

There are around half a million people in the air at any given moment

What can you do?

Realizing all this, the obvious thing to do seemed to be avoiding flying altogether. There are ways to travel while emitting little to no carbon, such as taking an electric car or a bike rickshaw. I've tried it myself and while it takes much longer, it's also really fun. But you can't carpool to India or take a solar boat to Russia.

It's easy to argue that if you truly care about the environment, you shouldn't travel so far. Just stay close to home. It's nice here in Europe, too, right? But those of us with friends and family spread across the globe know that even though you care about the environment and the future of the planet, you want to see your loved ones in person every once in a while. And then there are those who simply have to travel for work.

Why not take a self-made boat instead of a car? It's more fun - and better for the environment

So if you absolutely have to take a plane, here are a few things you can do to spare the environment, at least a little.

Make the most out of your trip

I'm not saying go to as many landmarks as possible, bungee jump off the highest bridge and swim with dolphins, sharks and penguins (like I did). You can obviously do that too, but that's not going to make your trip any more environmentally friendly.

Instead, make the most out of your trip by staying as long as possible. Don't simply fly somewhere for a weekend - that's not very sustainable. It creates a lot of emissions for very little benefit. Instead, maximize your time. Try to combine flying abroad for your mom's birthday or your best friend's wedding with your annual holiday so that you only need one long-haul flight a year.

Unfortunately, the trend in tourism is the exact opposite, says Susanne Becken, professor of sustainable tourism at Griffith University in Brisbane, Australia. "The trend is more trips, further away, for shorter lengths of stay," she told me in an interview.

Now that's not great for our planet, so let's try and reverse that trend, shall we?

To help save the Earth, stay in one country as long as possible, says DW's Anne-Sophie Brändlin

Choose your airline wisely

If your wallet allows, don't choose your flight for price and convenience. Your choice of route and airline make a difference when it comes to the environment, too. A flight with multiple stopovers and detours is often cheaper, but also releases far more carbon into the atmosphere. It's better to take a direct flight with a modern airline, using more efficient planes. Many airlines also give you information on your flight plan, telling you exactly how big your carbon footprint will be on their flight.

Your fellow passengers can also make a difference. While it's a treat to be on an empty flight where you can stretch out over an entire row, an airline that tends to fill their planes is the greener option. As much criticism as charter flights often get, that's one advantage they offer, says Becken. "They have a high carbon efficiency because they get the plane full."

When it comes to CO2 emissions, every kilo on board counts

Pack lightly

Think twice before bringing along that extra suitcase, because when it comes to CO2 emissions, every kilo of luggage counts. So leaving that extra pair of shoes at home is not just going to make life easier as you schlep your luggage around - it's also a nice thing to do for the environment.

And while it's awesome to make use of duty-free prices, why not buy those three bottles of wine at the duty free shop at your final destination, rather than carrying them onto the plane and flying them across the world. Small things like these can make a difference, says Becken.

The lighter you pack, the freer you'll feel - and the environment will thank you

Offset your carbon

The growing trend of "carbon offsetting" means you can now buy your way out of the environmental damage you cause - at least that's the idea. Basically, you pay a company to invest in a project that reduces your carbon emissions elsewhere, for example by planting trees that eventually remove carbon from the atmosphere, usually in a developing country.

On my recent return flight from Berlin to Cape Town, I produced 4.7 tons of CO2, as any carbon footprint calculator online will tell you. In order to buy myself a clean conscience, I could simply invest 64 euros in a reforestation project in Kenya, or 87 euros in a tree-planting project in the United Kingdom.

At least that's the amount of money carbon offsetting company "Carbon Footprint Ltd." calculated for me on its website - but there are lots of other companies and programs available online. The trees planted with my money would eventually remove CO2 from the atmosphere.

I could also spend 47 euros on supporting projects with the climate framework's Clean Development Mechanism, which invest in energy from wind, solar or biomass. That way, I can help prevent the creation of further emissions by supporting a company in buying a solar panel, for instance.

Carbon offsetting companies calculate your carbon footprint and what investment you would need to neutralize it

The problem is, the emissions from my flight are still in the earth's atmosphere. Buying carbon offsets simply helps make up for it in another way.

"Once the carbon is out there, it's out there, there's not much we can do," says Becken. "But that doesn't mean carbon offsetting isn't beneficial - it is. Even though the money is more of an environmental donation than a direct reduction of carbon, it's still helpful."

No regulations for aviation industry

But it's not just up to travelers to change things; the aviation industry itself must also be held accountable. Yet so far, there is no framework for that.

At the climate summit in Paris last December, almost every nation on this planet agreed to guidelines setting emissions cuts each must make to cut keep global warming below 2 degrees. But that calculation doesn't include airlines.

A roundtrip from Berlin to Cape Town spews more than 4 kilos of CO2 into the atmosphere per passenger

This is because it's hard to pinpoint which country is responsible for CO2 emissions from international flights. An important meeting is scheduled for September 2016, says Becken, when aviation companies will discuss a global framework that is supposed to regulate how much carbon emissions each airline is allowed to emit.

Until these self-imposed limits have an impact, it's up to you and me to make sure we keep our flying habits in check.

So are we doomed?

"Aviation is one of the fastest growing industries, at 5 percent a year," says Becken. And the trend is continuing. According to projections by the United Nations, cumulative passenger miles will rise to 7 trillion by 2030. In Europe and North America, the number of miles flown is forecast to double by then. But the fastest growth is expected in Asia and the Middle East.

Around the world are currently 1.2 billion tourists traveling outside their countries' borders for at least one night, with airplanes their most frequent choice of transport. In China, there are yearly 3.5 billion domestic trips - close to three times the number of global international tourists.

There are currently 3.5 billion domestic trips taken in China - but what if some of these become international trips?

Now picture just a third of these domestic Chinese tourists starting to travel overseas. That would immediately double the number of people already flying abroad. Our planet hurts just thinking about all those emissions.

"We have to start thinking of creative solutions," Becken says. One idea would be that every international tourist has to pay one dollar per year into a global tourism carbon reduction fund, she says. That would create $1.2 billion per year that could be invested, for example in carbon offsetting programs. "Airlines could for instance spend this money on putting a solar panel on every hotel," she says.

According to Becken, it's time to think outside of the box. "The average occupancy of planes is currently 80 percent. Ultimately, we need a globally connected data network that allocates free seats like free rooms on AirBnB," she thinks. "We need to maximize efficiency, relocate resources and basically start a digital revolution."

Does feeling guilty help?

So, after reading all of this, should you feel guilty for traveling? The simple answer is no.

"Research shows that appealing to people's ethics and guilt has only limited effect," says Becken. "Guilt is a negative emotion. It makes people feel like we are doomed anyway. What helps more is creating experiences for tourists that they enjoy and that at the same time are low-carbon and sustainable."

Could the world's largest solar plant become a tourist attraction?

One example would be to turn massive solar plants, like the world's largest one in Morocco, into a tourist attraction. "That way people who travel to Morocco anyway could learn about renewable energy, invest in sustainable projects and have a positive feeling about it," Becken says.

So the bottom line is: Don't despair - and start thinking outside of the box. There are so many small things we can do to protect the climate.

And if we all band together, we can truly sit back, relax, and enjoy the flight.