Pope Francis has unveiled an encyclical—a rare and influential Vatican statement—on climate change and the environment.

The highly anticipated document says that global warming is real, is caused partly by human activity, and is a grave threat to humanity. The Vatican hopes it will pave the way for a strong international climate deal later this year when diplomats descend on Paris for United Nations talks. But Pope Francis wants the encyclical to be read by everyone—and the Vatican hopes that the document will influence much more than just the Paris talks.

And just so his message is clear, the Vatican's official Twitter account, @Pontifex, has been active Thursday morning with blunt views from the pope. "The earth, our home, is beginning to look more and more like an immense pile of filth," reads one tweet.

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Here are six key points from the encyclical.

Population Control Is Not the Answer

For Pope Francis, caring about the environment goes hand in hand with taking a strong stand against abortion. "Since everything is interrelated, concern for the protection of nature is also incompatible with the justification of abortion," the encyclical says. "How can we genuinely teach the importance of concern for other vulnerable beings, however troublesome or inconvenient they may be, if we fail to protect a human embryo, even when its presence is uncomfortable and creates difficulties?"

Francis suggests that efforts to slow population growth are misguided and a distraction from the underlying cause of the world's environmental crisis—the hoarding of the Earth's resources by the rich and powerful. "To blame population growth instead of extreme and selective consumerism on the part of some, is one way of refusing to face the issues," the encyclical says.

This Isn't Just About the Environment

While the encyclical is centered around climate change and the environment, the overall message takes broad swipes at the consumer culture and calls for humans to cut back. "We seem to think that we can substitute an irreplaceable and irretrievable beauty with something that we have created ourselves," Francis writes, one of several times he warns about the dangers of technology created without a thought to its long-term impacts.

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The encyclical also takes a broad look at humans' overall relationships with each other, saying that development in the last century has "not always led to an integral development and an improvement in the quality of life" and highlighting effects like social aggression and drug use. Even the digital revolution gets a mention: "Today's media do enable us to communicate and to share our knowledge and affections. Yet at times they also shield us from direct contact with the pain, the fears, and the joys of others and the complexity of their personal experiences."

International Action Is Needed, But Only the Right Kind

The encyclical says that governments need to think as "one world with a common plan," saying that individual nations may not always act in everyone's interest or have enforceable measures on their own. But Francis also expresses disappointment with international negotiators in the past, saying that 2012 talks in Rio de Janiero only produced "a wide-ranging but ineffectual outcome document," in part because developed countries were only thinking of their own self-interests. Other more narrow agreements, like the Basel Convention on hazardous waste or the Vienna Convention on the ozone layer have been more effective, though.

But Francis says that only the right kind of international deal can produce results. An agreement that imposes the same responsibility on all countries regardless of their development level, he says, would penalize the Third World. That acknowledges—but does not necessarily solve—one of the biggest hang-ups in previous international talks, where developing countries have balked at massive reduction targets. "Common and differentiated responsibilities" will have to be considered in the Paris talks, Francis says, to help developing countries.

One solution that Francis swiftly dismisses is a deal that would use carbon credits in a cap-and-trade scenario. That solution would not "allow for the radical change that present circumstances require," he says, adding that it "may simply become a ploy that permits maintaining the excessive consumption of some countries and sectors."

The Water Crisis Is Real, So Put Down That Bottled Water

Francis—the first pope from the developing world—highlights the broad impact that climate change is having on the poor, but he takes steps to emphasize some specific impacts. One chapter looks at the water crisis, saying that global warming has depleted freshwater resources, while industrial activity and chemical pollution has polluted drinking water in poor places. Building on the theme of limiting consumption, Francis laments that, "in some places, there is a growing tendency, despite its scarcity, to privatize this resource, turning it into a commodity subject to the laws of the market."

A water shortage could have huge ramifications for agriculture and public health, he says, adding, "It is also conceivable that the control of water by large multinational businesses may become a major source of conflict in this century."

Pesticides Pollute and GMOs Are a Complex Issue

Francis takes on pesticides in a section of the encyclical focused on "pollution, waste, and the throwaway culture." After noting that daily exposure to pollutants can create serious and even deadly health risks, the pope says that "fertilizers, insecticides, fungicides, herbicides, and agrotoxins in general" cause pollution that impacts everyone.

Francis also delves into the controversy over genetically modified organisms. The pope notes that genetic modification of plants and animals is not a new phenomenon but one that exists in nature and has also been carried out by humans for years. "It is difficult to make a general judgement about genetic modification (GM)," the encyclical says.

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But Francis still strikes a note of caution: "Although no conclusive proof exists that GM cereals may be harmful to human beings, and in some regions their use has brought about economic growth that has helped to resolve problems, there remain a number of significant difficulties that should not be underestimated." Francis warns that "the expansion of these crops has the effect of destroying the complex network of ecosystems [and] diminishing the diversity of production."

The Pope Thinks You Should Ride the Bus

Francis links the quality of life in cities to how we get around. Too many cars on the road cause traffic jams and pollution and suck up fossil fuels, the encyclical notes, adding that overreliance on cars also leads to the construction of more roads and the paving over of the natural environment to create parking lots.

Riding the bus or the metro may be the antidote, the encyclical suggests. "Many specialists agree on the need to give priority to public transportation," the document reads, while praising the efforts that some countries have made in recent years to improve their public-transit networks.

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