Mass environmental destruction, known as ecocide, would become an international crime similar to genocide and war crimes under a proposed new legal definition.

The definition's unveiling last week by a panel of 12 lawyers from around the world marks a big first step in the global campaign's efforts to prevent future environmental disasters like the deforestation of the Amazon or actions that contribute to climate change.

There are currently four core international crimes: genocide, war crimes, crimes against humanity, and the crime of aggression. These crimes are dealt with by the Rome Statute of the International Criminal Court (ICC).

The Independent Expert Panel for the Legal Definition of Ecocide spent six months preparing the 165-word definition, working with outside experts along the way. In a draft of the definition by the Stop Ecocide Foundation, a Netherlands-based coalition, panelists said they hoped the proposed definition could provide a basis for the consideration of a new international crime.

So, what's the proposed definition?

The draft defines ecocide as "unlawful or wanton acts committed with knowledge that there is a substantial likelihood of severe and either widespread or long-term damage to the environment being caused by those acts."

Unlike the existing four international crimes, ecocide would be the only crime in which human harm is not a prerequisite for prosecution.

"There are elements of human harm that can be included in (the definition), but it also extends to damage, per se, to ecosystems," said Jojo Mehta, chair and co-founder of the Stop Ecocide Foundation. "So effectively you're looking at something that has, at least in part, potential to be a crime against nature, not just a crime against people."

The original ecocide proposal is almost 50 years old

The intent to make ecocide an international crime isn't new. The idea was brought up by then-Swedish Prime Minister Olof Palme at the 1972 U.N. Conference on the Human Environment. In his speech, he warned that rapid industrial progress could deplete natural resources at unsustainable levels. But even before that biologist and bioethicist Arthur Galston used the word "ecocide" at the 1970 Conference on War and National Responsibility in Washington, D.C.

Several other attempts at formalizing ecocide as an international crime have emerged since then. Ecocide was considered and then dropped during the formal establishment of the ICC in 1998. For 10 years until her death in 2019, Scottish barrister Polly Higgins campaigned for ecocide to be recognized as a crime against humanity. The Stop Ecocide Foundation took up the challenge in 2017.

A proposed definition is just the start of a long process

What would it take for the ICC to adopt the ecocide definition and amend the Rome Statute? A lot. Here are the steps that would need to happen:

1. One of the International Criminal Court's 123-member countries (which do not include the U.S., China or India) would have to submit a definition to the United Nations secretary-general
2. The proposal must then be voted on by a majority of members of the ICC at the annual assembly in December in order to be considered. 
3. Once the final text for an amendment is discussed and agreed upon, two-thirds of member countries must vote in favor. 
4. The vote is ratified and must be enforced in countries a year later. While it will become a criminal offense in the countries where it is ratified, ratifying nations may arrest non-nationals on their own soil for ecocide crimes committed elsewhere. This means citizens of countries that are not members of the ICC could still be affected.

Between the formal proposal of an ecocide crime by a member country and ratification, however, an amendment process could take years to decades. The court would hold a vote at their annual meeting in December to take up the proposal, and after that, debates would begin to finalize the crime's definition.

Despite this, Mehta says that rapidly growing conversations and support around the subject have given the panel confidence.

"We don't see any likelihood of it disappearing. The likelihood is it will actually get proposed," she said. "However, even if it takes longer than we would like ... just the fact that this conversation is happening is already making a difference."

The International Crime Court has not yet commented on the panel's proposal.

Josie Fischels is an intern on NPR's News Desk.