the law will hold them liable for their actions.

But who would you take to court over storms, floods and droughts?

This episode will show the ways in which the law

is helping us all deal with this increasing problem.

The Peruvian farmer taking on a German energy giant over pollution...

And how the world around us might get a whole load more legal protection...

Humans have been polluting the world for a long time.

So, how can you take action about something like climate change?

Who would you blame?

It's not any one person, company, country, or government's fault...

...or is it?

This is Saúl Luciano Lliuya.

He's a Peruvian farmer and mountain guide,

and for years he has watched a glacier, in nearby Huaraz,

melt due to climate change.

So, he decided to do something

and chose to sue a German energy company, RWE.

He's asking for around €17,000

to help him cope with climate change.

It's a number based on the share of manmade emissions

he claims RWE is responsible for.

RWE say there's no direct link

between them and the melting glaciers.

His hope is that his case would make it easier

for thousands or even millions of others like him

to do the same to protect their homes.

And that could mean energy companies are forced

to change the way they do business,

or risk losing billions of dollars in court.

RWE say there's no direct link

between emissions in Germany and melting glaciers in Peru.

Noah Walker-Crawford, from the University of Manchester,

has worked with Saúl's case.

He explained why Saúl is taking action.

Saúl can see the impacts of climate change in Peru

every day with melting glaciers,

but he feels like it's not him

or it's not Peruvians who have caused this problem,

but it's rather big companies in other parts of the world,

who've caused climate change through their pollution,

and that's why he's taking this German company, RWE, to court,

arguing that they've made a big contribution to climate change,

which has caused big impacts in Peru.

Saúl argues that RWE and other companies

have caused climate change, which is affecting him:

the melting glaciers are partly their fault.

What kind of laws is he using?

To try and hold RWE responsible,

what Saúl is doing with his lawyers

is basically applying neighbourhood law.

So, they're using the kind of law you'd use

to resolve conflicts between different neighbours.

So, basically Saúl is saying to RWE:

'You're my neighbour in a global context,

because you're causing me harm or risk of harm via –

through climate change, and as a neighbour,

  you need to take responsibility for this harm you're causing me.'

Saúl is using similar law to the kind used

to solve arguments between neighbours –

just in a global way, rather than locally.

So, why could this one case be important?

So, this lawsuit is obviously only against one company

and it's over a small amount of money, around $20,000,

which is small change for a big company like RWE.

But what this is really about is about setting a precedent.

So, about developing legal tools

to hold big greenhouse gas emitters, big companies, responsible.

And so if Saúl wins this case against RWE,

other people who are affected by climate change

could use a similar legal approach

to sue lots of other companies in lots of other countries.

This case could set a precedent:

other people would copy Saúl and take on many other companies.

So, what could I do, if I had a case like this?

If you want to take action on climate change,

if you want to go to court,

that's a very difficult and complicated approach,

because it costs a lot of money and it takes a long time.

And actually what we really need is political solutions on climate change,

because the solution isn't going to be that everyone

who's affected will take a big energy company to court.

And what these kinds of lawsuits do, like Saúl's lawsuit,

is that they put pressure on politicians to find long term solutions.

Going to court takes a lot of time and money in a case like this.

Noah wants political solutions to climate change.

Saúl's case shows an interesting approach:

he's trying to get money he thinks he's owed for damages to his life.

But what if you just want to protect the environment itself?

Laws are agreements between people or groups of people.

By living in a society, I've agreed

that if I break the rules, I get punished.

We've seen that lawyers are using laws which give rights to people

to protect the environment.

But that's complicated.

What if I want help with a problem like melting ice caps?

It's hard to say exactly who's being harmed

and how much they're being harmed,

so that makes it hard for lawyers to take action.

Could that all be about to change?

We spoke to lawyer Philippe Sands,

who's part of a group that wants the international community

to set up a new crime called 'ecocide'.

It would sit alongside things like war crimes

and crimes against humanity.

It would directly protect the environment.

He explained more.

And our definition of 'ecocide' is unlawful or wanton acts,

which a person commits in the knowledge

that there is a substantial likelihood

of severe damage to the environment,

which is also widespread or long-term.

So, the heart of it is severe damage to the environment.

'Ecocide' would be breaking the law in a way that meant

doing something that seriously damages the environment.

Why aren't our current laws good enough?

The law tends to lag behind. It follows; it doesn't lead.

And environmental consciousness is a new thing.

So, we're living today with the laws of the past

and this project, defining the crime of 'ecocide',

is about updating our laws to the current situation.

It takes time for laws to be written.

Environmental awareness is relatively new;

the law needs to catch up.

So, does he think 'ecocide' will become law?

It will now be for states, for governments,

to decide what to do with it.

If five or six governments decide they want to run with this idea,

I think it is likely to take off. My sense is that

there will be governments who want to run with this idea,

so I'm quietly optimistic.

International laws need governments to agree to them.

If six or seven governments agree, it might be possible.

So, what could stop 'ecocide' becoming a crime?

There will be a number of countries

and a number of corporations, who will be very worried that,

  if a crime of ecocide becomes part of international law,

they will be targeted.

And so the objections will come, I suspect,

from countries and corporations who benefit the most

from widespread and severe damage to the environment.

Companies and countries who damage the environment most

might oppose it becoming international law.

So, we've seen how some people can take on the people

they think are behind climate change,

in an effort to get widespread change.

And if the crime of 'ecocide' enters international law,

courts could have whole new powers

to protect us and our world.