The encyclical letter Laudato Si is available here on the Vatican website.
170. Some strategies for lowering pollutant gas emissions call for the internationalization of environmental costs, which would risk imposing on countries with fewer resources burdensome commitments to reducing emissions comparable to those of the more industrialized countries. Imposing such measures penalizes those countries most in need of development. A further injustice is perpetrated under the guise of protecting the environment. Here also, the poor end up paying the price.
Climate change has already impacted agriculture in the Middle East. Even if terrorism weren’t the issue, many refugees flee homelands because they can no longer sustain themselves as they once did.
Furthermore, since the effects of climate change will be felt for a long time to come, even if stringent measures are taken now, some countries with scarce resources will require assistance in adapting to the effects already being produced, which affect their economies. In this context, there is a need for common and differentiated responsibilities. As the bishops of Bolivia have stated, “the countries which have benefited from a high degree of industrialization, at the cost of enormous emissions of greenhouse gases, have a greater responsibility for providing a solution to the problems they have caused”.[Bolivian Bishops’ Conference, Pastoral Letter on the Environment and Human Development in Bolivia El universo, don de Dios para la vida (March 2012), 86]
If First World industry has contributed to the degradation of agriculture in other places in the world, I think First World countries would totter into immorality by closing borders to the problems they have created.