(someone) is in charge of (something)

There are two ways that we use "in charge of ___". First, you can be "in charge of" a specific job or duty:

Eric, you're in charge of the food. Takeru is in charge of booking the DJ and so on.

Or you can be "in charge of" a person or a group of people:

When you're in charge of a team of over 30 people, it's pretty stressful.

In both cases, being "in charge" means that you are the leader or the person who's responsible.

sustainability

Something that is "sustainable" can be continued for a long time.

The important thing when you're preparing for a race is to pick a sustainable pace. Don't run so fast that you tire yourself out and have to stop.

"Sustainability" is a noun that describes this idea of being able to continue something for a long time. But more specifically, we often use this word to talk about environmental sustainability. That means the ability of the Earth's environment to continue to function well.

As an example, imagine a company that manufactures paper. At that company, there might be a "Sustainability" department which makes sure that the company uses more recycled paper, and that more trees are planted to replace the ones that they use to make the paper.

You can use the word "sustainability" like this:

We need to think not only about short-term profits, but also about sustainability.

a (something) initiative

An "initiative" is a large project. The goal of an "initiative" is to make large changes in an organization, like a company or government agency.

Initiatives are given labels like:

• the reform initiative
• an education initiative
• our technology initiative