Ecological researchers who use remote sensing techniques get to have a lot of fun. They make maps documenting spatial and temporal patterns of where creatures and plants are migrating to and they describe the patterns they see. These papers get published in big journals and grant money flows. The NY Times has a fun piece today on this subject. The point that Justin Gillis makes is that in the past there were cold winters that acted to kill off creatures and plants so that they didn't migrate north. With warmer winters, these creatures and plants are on the move and are invading the turf of other creatures. The fight is on for scarce land! An economist might ask a few questions;
1. How do we know what is the "right" mix of creatures and plants? I would guess they would say that that we need a stable equilibrium so that no creature goes extinct and we preserve bio-diversity. In an economic capitalist system, such an equilibrium would be brought about by markets and market prices so that net demand for resources equals zero at market clearing prices. Given that most creatures and plants do not participate in markets, how will climate change affect the spatial distribution of creatures and plants? Are such changes a bad thing? If there were property rights to land, then Mangroves would purchase this land from the current owners. Instead, in the case of Mother Nature --- there is an "invasion army" as the big bad Mangroves do not get killed off by cold weather and instead march north. If Mangroves win a competition under the new climate conditions, is this "good" or "bad"? If we don't know the answer to this, how could this question be answered? If ecologists can't answer the question of what is the right mix of biodiversity for a specific geographic area or for a state, a nation or for the globe, why is that the case? Are ecologists ambitious enough to seek to write out a social welfare function? Martin Weitzman explored this in this famous paper.
2. Note that unlike urbanites, these plants and creatures live their lives outdoors. There has not been enough thought given to how buildings and other capital investments shield us from climate conditions and climate risks. Yes, our food is grown outdoors but it could be grown indoors. Also, in a world with international trade there are many places where it could be grown. Diversification is a word that climate change scientists will learn soon enough.
Yes, just like people, nature will migrate in response to new climate conditions. Given scarce land, there will be a competition for which people and creatures value the scarce input the most. Unlike other creatures, we can build vertical structures called buildings to stack ourselves in lower risk places. These creatures are less able to substitute capital for land and this gives us urbanites a huge advantage in adapting. Read Climatopolis and start to think about these issues. Gillis wants to extrapolate to men from the mangroves but he needs to think through his urban economics first.