You’ve probably experienced something like this before.

You’re about to buy a cup of coffee when the barista asks,
“Did you bring a tumbler?”

You actually care about reducing waste. But today, you didn’t bring one.

For a moment you think:

“It’s just one plastic cup. Everyone else is using one anyway.”

Or maybe you’ve considered taking public transportation. But you notice your friends still ride their motorcycles or drive their own cars, and you tell yourself:

“Maybe later—when the system gets better.”

If you’ve ever felt this way, it doesn’t mean you don’t care about the environment.
What you’re experiencing is actually a common decision pattern explained in game theory.

What Is Game Theory?

Game theory is a framework for understanding decisions when the outcome depends on the choices of other people.

It’s not about games played with controllers or joysticks. Instead, it refers to the strategic interactions that shape real-life decisions—in teamwork, business negotiations, politics, and even climate action.

At its core, game theory asks a simple question:

“If I choose to act, what will others do?
And if they act that way, what is the best decision for me?”

In many situations, our choices are not purely individual. They are shaped by what we expect other people to do.

Why Game Theory Matters for Climate Change

Climate change is fundamentally a collective problem.

If many people act together, the impact can be significant. But if only a few take action, those individuals may feel as if they are carrying the burden alone.

In game theory, this situation is often described as the free-rider problem: people enjoy shared benefits—cleaner air, healthier ecosystems, and more livable cities—without contributing to the effort required to achieve them, such as reducing emissions or waste.

Because of this dynamic, many people end up choosing what feels like the safest strategy: following the crowd.

Three Everyday Situations Where Our Decisions Depend on Others

1. Coffee and Tumblers: “What’s the point if it’s just me?”

If only one person brings a reusable tumbler, the impact may seem small. But if an entire campus or city adopts the habit, the difference becomes significant.

The problem is uncertainty. You’re not sure whether other people will participate. And because of that uncertainty, it’s easy to think:

“Maybe later.”

This hesitation isn’t about laziness.
It’s about the natural reluctance to be the only one making the effort.

2. Transportation: “I want to—but the system isn’t ready”

You may already know that public transportation or carpooling is more climate-friendly. But if:

• the access is inconvenient,

• the schedule is unreliable, and

• most people around you still use private vehicles,

then driving your own vehicle often feels like the most practical option for that day.

Game theory helps us see something important: individual choices are often shaped by collective conditions.

3. Thrifting: “What if people judge me?”

Thrifting can be affordable, stylish, and a great way to reduce the environmental impact of fast fashion.

Yet some people hesitate because they:

• worry about being perceived as unable to afford new clothes, or

• feel uncomfortable standing out within their social circle.

However, if social norms shift—even slightly—thrifting can quickly become normal. And once something becomes socially accepted, many people will adopt it without hesitation.

So What Does This Mean for Climate Action?

The solution is not simply telling people to “care more.”

Game theory suggests something deeper: change the conditions under which decisions are made.

If we want more people to take environmentally friendly actions, those actions need to become easier, fairer, and more socially visible.

Here are several approaches that work well from a game theory perspective.

1. Make Sustainable Actions Beneficial (Incentives)

Incentives can make a big difference, such as:

• discounts for bringing your own tumbler

• reward points for refill systems

• benefits for carpooling

• community recognition for environmental initiatives

This is not about “paying people to care.”
It’s about reducing the feeling that one person is bearing the cost alone.

2. Clarify the Rules of the Game

Within communities or organizations, clear roles, expectations, and targets help people feel that responsibility is shared.

When the rules are transparent, cooperation becomes easier.

3. Make Participation Visible (Social Influence)

People are strongly influenced by what they see others doing.

When individuals notice their friends, colleagues, or communities adopting sustainable habits, those behaviors begin to feel normal—and normal behavior spreads quickly.

4. Remember: This Is a Repeated Game

Climate action is not a one-time decision. It’s a repeated interaction.

When you and your social circle consistently take small actions together, trust grows, the feeling of acting alone disappears, and cooperation becomes more stable over time.

Start Small—But Make It Social

If you want to try something practical, here are three simple actions that can have real impact because they involve others:

• Create a “tumbler team” with a friend
  Bring reusable tumblers together and remind each other until it becomes a habit.

• Try carpooling once or twice a week
  Take turns driving. The impact is real—and it becomes easier when more people join.

• Start a thrift challenge
  Buy one thrifted item each month and share the outfit—not to show off, but to help normalize the idea.

Because sometimes climate change isn’t only about advanced technology or large-scale policies.

Sometimes it begins with small moments that make someone else think:

“Oh… a lot of people are actually doing this.
Alright, I’ll join in.”

And that’s when the game begins to change.

FAQ

Is game theory only used in economics?

No. Game theory is widely used to analyze strategic situations in many fields, including organizational behavior, political science, conflict resolution, and environmental cooperation.

Why is it so difficult for people to coordinate on environmental issues?

Because the benefits are shared by everyone, while the effort or cost often feels like it must be borne individually. This dynamic encourages free-riding and the tendency to “wait for others first.”

What makes climate action more effective?

Climate action becomes more effective when cooperation is the most rational choice—through clear incentives, transparent rules, visible participation, and strong social support.


Contributors:

Meiardhy Mujianto