2012, he became an associate with E3G working on an assessment of the development potential of the North Seas Offshore Grid Initiative in a project which was supported by the European Climate Foundation and the Children's Investment Fund Foundation. In 2013, he organised two climate gatherings which brought international climate experts to Ireland to examine what new narratives are needed to increase public support for action on the climate issue. He was the Green Party candidate in the Dublin constituency at the 2014 European Parliament election, but was not elected. He was elected a TD for the Dublin Bay South constituency in the 2016 general election, alongside deputy leader Catherine Martin who secured a seat in Dublin Rathdown. The Greens' return to the Dáil following their wipeout in 2011 was the first time in Irish election history that a political party had been able to survive losing all their TDs. In 2019, Ryan called for wolves to be reintroduced to Ireland. Fine Gael rejected this suggestion, with Minister for Culture, Heritage and the Gaeltacht Josepha Madigan responding that her department had no plans to reintroduce wolves into the country, saying that the "large predator" doing so would do damage to farming. He reiterated the following January that he would like to see them introduced in his lifetime. Also in 2019, comments he made on car use in rural Ireland which were published in an article by The Irish Times was criticised online. The newspaper also stated that Ryan suggested that a village of 300 people needs just 30 cars to operate. In the article, Ryan stated people could walk to a pick-up point or cycle. Responding to the article, the party took issue with the headline, and in a statement said the original headline ("You don't need to own a car to live in rural Ireland" - Green Party T.D') had caused “a flood of online fury – and rightly so, because a suggestion like that would be ridiculous and impractical”. In February 2020, the Green Party had its best election result in the general election of that year, with the party increasing its representation in the Dáil to 12 TDs. Ryan was re-elected in the Dublin Bay South constituency, topping the poll with 22.4% of the first-preference votes. In March 2020, in a speech in a debate on responses to the COVID-19 pandemic crisis, he made comments on growing