Behind the glory of hallyu dramas are the star-studded casts.

After garnering attention abroad in Korean dramas — mainly other Asian countries including China and Japan — stars quickly jump into dramas and variety shows there

Overseas endorsements, and fan meetings follow, consolidating their positions, as well as the prominent status of hallyu.

Starting with the unexpected success of the KBS2 TV drama series “Winter Sonata” which aired on Japanese satellite channel BS2 in 2003, the drama’s protagonists Bae Yong-joon and Choi Ji-woo enjoyed a meteoric rise as the first hallyu drama stars.

Lee Young-ae, who starred in MBC TV drama “Jewel in the Palace” the following year, replicated the two stars’ success, keeping hallyu alive.

The SBS hit drama “My Love from the Star” which recorded 2 billion views on Chinese video platform iQIYI in 2014, set a milestone for hallyu dramas.

Kim Soo-hyun, until then best known for KBS2 series “Dream High,” MBC fusion historical drama “Moon Embracing the Sun,” and webtoon-based film “Secretly, Greatly,” became active in China after the international success of “My Love from the Star,” where he played the male lead Do Min-joon.

Kim has appeared in local variety shows in China including Jiangsu TV’s “The Brain” and “Bring You To The Stars” in 2014 and Sohu TV’s “Stars From Korea.” In 2014, Kim was also reported to have set a new record by signing 35 endorsements deals, 16 of them in China.

Park Hae-jin, another male lead of “My Love from the Star,” has built up a career as a hallyu star in a slow and steady way, unlike his contemporaries. Even before the SBS drama became popular in China, Park had appeared in Chinese TV dramas starting in 2011 including Hunan TV’s “Another Kind of Splendid Life,” Xi An TV’s “Loves Relativity,” in “Secret Society of men — Friends” which aired on four Chinese channels including Zhejiang TV and Dongfang TV last year, and Guangdong TV’s “Far Away Love” this year.

Park also played the male lead in the tvN drama series “Cheese in the Trap” this year, which will be released on Chinese websites Youku and Tudou this summer. He was reported to have signed endorsements with 15 advertisers this year, estimated to be worth 11 billion won in total.

Meanwhile, the hottest hallyu rookie Song Joong-ki is enjoying popularity in China as KBS2 TV drama series “Descendants of the Sun” is being broadcast simultaneously in China on iQIYI.

Song, who debuted in the film “A Frozen Flower” in 2008, shot to stardom in 2010 with KBS2 fusion historical drama “Sungkyunkwan Scandal.”

While carving out his position as an entertainer by appearing on SBS variety show “Running Man” from 2010 to 2011 and on KBS music programme “Music Bank” as an MC from 2009 to 2010, Song continued to build up his acting career.

After serving in the military, from 2013-2015, Song made a strong comeback with “Descendants of the Sun,” which has made him the hottest star of the moment.

The KBS2 TV drama hit 400 million cumulative views on iQIYI, out-performing “My Love from the Star.” It will also begin airing on the Japanese cable channel Elsei Gekijou in June.

Every day, every person on this planet makes many decisions. From the moment we wake up to the time we fall asleep, we make choices that range from what we will wear to how we will get to work and where we will shop.

More than a dozen of these decisions are about food: what to eat, where to buy food and how to cook it.

Today, as people all over the world get ready to show their commitment to the health of the planet by turning off their lights for one hour, it has become even more important for us to realise how each of these decisions can have a huge impact on the world we share.

The need for this is as clear as the air we want in our cities. Within the next 35 years there will be an extra 1.5 billion people to feed, each with his/her own dream and aspiration.

By 2030, humanity will need the equivalent of two Earths to support itself. This is clearly not viable in a world where climate change will make it even harder for the natural world to provide for our needs.

It is tempting to ignore these problems, partly because we feel that one person cannot make a difference.

But we are not alone in this world, and individual action forms part of a greater whole. As Xunzi, the famous Confucian philosopher, once said: “No river or sea can be formed without the streams.”

But how can we make our individual streams flow the way they should? A large part of the answer lies in making wise decisions about the things we do every day.

For example, we can think about how and what we eat. I was shocked to learn that it takes more than 16,000 liters of precious water to produce just 1 kilogram of beef.

Most of the forests we chop down are destroyed to make way for animal agriculture, which makes meat production the leading cause of species and biodiversity loss.

And, as if this wasn’t bad enough, the meat industry accounts for almost one-fifth of all the man-made greenhouse gas emissions that drive climate change.

So, something as simple as eating less meat can help save two of the world’s most precious resources – our water and our forests – while combating climate change.

We also need to be better at conserving food. Every year, humans throw away about one-third of all the food we produce – about 1.3 billion tons.

This is particularly horrifying when you think of the millions of people who don’t have enough to eat. By shopping smartly, planning our meals and creatively using our leftovers we can prevent this shocking waste of food, and save money too.

Another way of saving money and the environment is to replace the light bulbs in our homes and offices with more energy-efficient ones. If everyone on the planet did this tomorrow, we’d stop the equivalent of 138 coal-fired power stations from spewing out harmful carbon dioxide into the atmosphere every year.

With China’s electric car market set to more than double in 2016, we can also think about buying an electric car when it’s time to trade our old one. Or we can choose to ride to work on a bicycle, use public transport or share a ride to work.

Each day here in China we face the consequences of failing to make these simple, educated choices: we are reminded of this failure every time the government issues a smog alert and every time our children can’t go to school because of the harmful air pollution.

For our health and well-being, the cost of failing to act is as damaging as the smog that shrouds our cities.

Confucius taught us frugality and thriftiness, and these two principles need to be in our minds whenever we go out shopping – we need to use our financial and natural resources wisely as “Green Consumers”.

When we need to buy new appliances and goods – be it a washing machine, refrigerator, car, cosmetics or electronics – we need to buy ones that carry the government’s eco-label.

By making these small, smart and simple changes to the way we live, we can start to enjoy better health, a better environment and a better bank balance.

Today, as the world marks Earth Hour, we must realise that making the world a better place isn’t just about switching off our lights for a short time.

It’s about changing the way we live; it’s about changing the way we consume so that the billions of decisions we make collectively don’t destroy the planet but help to protect it instead.

By setting our hearts right and by cultivating our personal life, we can put the world in order.

This is not only about being kind to future generations; it’s about being kind to ourselves and our communities today.

The author is a goodwill ambassador of the United Nations Environment Programme.