Teenage climate activist Greta Thunberg is currently sailing across the Atlantic Ocean on her way to a climate conference in the United States. This is just the latest in a string of activities and appearances she has participated in to raise awareness about human-caused climate change and convince governments around the world to take stronger action to fight against it.

Most famously, she started protesting the government in her native Sweden to take more action against climate change, which sparked massive school walkout protests all over the world.

While she may be young -- only 16, in fact -- her determination to act and try and do something for a cause she believes in has inspired thousands of people around the world. Her story also holds some lessons for aspiring entrepreneurs who want to make a difference. Lessons like these four: 

1. It's important to stand up for what you believe in.

Starting with the obvious, Thunberg is making her mark by standing up for what she believes in and encouraging others to do the same. As an aspiring entrepreneur, if you are looking for business ideas, start with your passions. Starting a business is a long, grueling process, and it helps if you are passionate about the industry you are in.

As you're developing your company, you can also try to follow your values. Whether that's supporting other local businesses, sourcing only fair trade supplies, or trying to make your supply chain as carbon neutral as possible, there are many ways to incorporate your values and beliefs into your business. 

2. You're never too young (or old) to make a difference.

You might be in college, just out of college or not even out of high school yet, but if you have a good business idea and you are dedicated, you can make it happen. At 15, Thunberg started out as a one-person protest and inspired thousands of people to act. Now at just 16 she's already addressed numerous large climate conferences and is on her way to talk to the United Nations.

Don't let your age stand in the way of making a difference in the world. One of the biggest benefits of starting your entrepreneurial journey at a young age is that you're also young and resilient enough to rebound from setbacks more easily than if you were older. (Although, I also believe you are never too old to start a business.) 

3. Regardless of what you are trying to do, there will be people working against you.

It seems hard to believe anyone would actively work against a child who wants to try and save the earth from destruction, but even this noble goal attracts haters, and Thunberg has to deal with more than her fair share of detractors who attack her on social-media platforms. No matter who you are and no matter how benevolent your ideas might be, you will have to deal with people who are actively trying to thwart you.

In the business world, those people may be competitor companies or government bodies that pass legislation that affects your business. Get to know the various threats to your business, so you are prepared for them. If you decide to take a stance on a political issue, your business could be targeted by people opposed to whatever you are standing for, so you also have to be prepared to deal with those potential consequences. 

4. Sometimes standing for what you believe in means making tough decisions.

For Thunberg, her environmental activism means no flying, as that form of travel has a big carbon footprint. Even her parents have reportedly stopped flying to accommodate her beliefs. If you want your business to reflect your values, that might mean making some tough decisions.

If you want to use only fair trade supplies in your business, for example, that would almost certainly mean paying more for them than available alternatives that are not fair trade. Or if you wanted to openly take a political stance, it might mean losing some customers. These are tradeoffs you will have to navigate in your business as you set it up and make important decisions about how it will run.

But as Thunberg has shown the world, determination and fighting for what you believe in can take you a long way.