A little more than four years after Pope Francis published one of his most provocative documents, not to mention perhaps his most political, in the form of his eco-encyclical Laudato Si, the pontiff appears increasingly disappointed in the way the environmental manifesto been received.

In two separate messages published this week, Francis appeared to suggest that the global resolve to combat climate change and other ecological threats his encyclical hoped to produce is failing, due a lack of commitment from the parties involved.

In a Dec. 4 message to the U.N. Climate Change Conference summit in Madrid, he said, “We must seriously ask ourselves if there is the political will to allocate with honesty, responsibility and courage, more human, financial and technological resources to mitigate the negative effects of climate change.”

Running Dec. 2-13, the summit, known as COP25, was intended to be a venue in which the U.N. identifies concrete strategies for the implementation of the so-called Paris Agreement of 2015, which provided a framework of climate action adopted in hopes of reducing greenhouse gas emissions enough to keep global temperatures from rising to a perilous degree.

Yet according to studies conducted by the Intergovernmental Panel on Climate Change, things are getting worse. Global temperatures and emissions, the study found, are still rising, making it difficult - if not impossible - to fulfill the goals of the Paris Agreement by 2020.

Similarly, in a conversation with Jesuits from East Asia during his recent visit to Thailand, Francis said the COP21 meeting was “truly a step forward” in the battle for environmental protection.

However, he lamented that conflicts bubbled up after Laudato Si and the Paris agreement, saying “compromises” were made between “what was assumed and the purse, the economic interests of some countries.”

He pointedly added that “some countries have withdrawn” from the agreement. Though he did not name names, it’s hard not to read the comment as a reference to U.S. President Donald Trump, who is currently the only global leader who has announced plans to withdraw from the Paris Climate accord.

Trump initially announced the withdrawal during his first year in office. Technically, however, a country is unable to begin a withdrawal until three years after the agreement went into effect, which for the U.S. was Nov. 4, 2019. It is expected that it could take more than a year for the U.S. to completely withdraw, and that the process might not be complete until after the 2020 U.S. presidential elections.

Should Trump fail to be reelected and his successor wish to rejoin the agreement, an application would be made and the U.S., or any other country that might withdraw, could be back in 30 days.

A highly anticipated document at the time of its publication, Laudato Si became a defining moment for Francis, who in the text argued that climate change was an almost entirely manmade phenomenon; called for the elimination of fossil fuels; and pushed for the adoption of an “integral ecology” which defended respect for human dignity as well as creation.

In the aftermath, there was a fair amount of blowback from some ecclesial circles, with some critics arguing that not only was the science behind the encyclical shoddy, but many collaborators in the document supported positions at odds with Church teaching, such as support for population control and abortion.

However, that did not dissuade global political leaders from welcoming and supporting the pope’s environmental efforts.

Though the Vatican has played a larger-than-usual role on the climate issue - retired Pope Benedict XVI himself was a major advocate for environmental protection - it has taken on a new push under Francis, who has been an active player in getting his climate agenda through via major international platforms, such as the United Nations.

Laudato Si itself was largely published to influence global discussion on the climate issue, as it came out just before the COP21 climate summit in Paris. Since then, climate change has been a major talking point between Francis and most world leaders he meets. Not only does he give a copy of the encyclical to every official or head of state he meets, but the climate issue frequently pops up in routine papal speeches.

In 2016, American actor Leonardo Di Caprio, a self-proclaimed environmental advocate, met with the pope for a private audience at the Vatican to discuss the issue.

In remarks to the 48 Jesuits present for the conversation in Thailand, the text of which was published on the Italian Jesuit-run newspaper La Civilta Cattolica, Francis said that people are generally “much more aware” of the need to care for the environment, especially among youth.

Though he didn’t name her specifically, he alluded to climate rallies led by Swedish teen Greta Thunberg and the student-led strikes she launched, saying the recent climate movements created by young people “are the road on which to walk” going forward.

“Today it is the young people who are able to understand with their heart that the survival of the planet is a fundamental issue. They understand Laudato Si with their hearts,” he said, adding that “we must continue to work so that the fundamental message that Laudato Si intends to communicate is shared worldwide.”