"Significant loss of species and biodiversity — Over the next 35 years, humans may make a concerted effort to preserve rare species by collecting them and housing them in zoos. "
The extremely dangerous effects of biodiversity cannot simply be handwaved out like this.
Firstly, this is impossible since the vast majority of species are unknown to science (remember that vertebrates and confierous plants only represent a small fraction of species). Actually obtaining viable samples from the 70,000 vertebrate species, 1,000,000+ invertebrate species, 300,000+ plant species and 100,000,000+ estimated bacterial species would be a herculean task of such magnitude that no one would ever pay for it. Let alone actually obtaining a genetically diverse pool - which would require at least 500 random individuals from each species. Zoos often have to trade individuals with each other and interbreed in order to maintain a genetically viable population.
But all of this is ignoring that we already have a zoo that houses all species and is perfectly capable of supporting all of them in the foreseeable future, and doesn't cost anything to run. The only thing it asks is that we not destroy it.
"Doesn't cost anything to run" is silly. If maintaining the ecoysystem was free, we'd do it because most people prefer there to be one rather than not. Maintaining the ecosystem trades off against all sorts of other things we want, and if we have to give them up to maintain it, that's what it costs to run.
According to a recent press release from UC Berkeley’s School of Law:
Guzman's view is shared by many.
While I have not read Guzman’s book, I have read GiveWell’s summary of the IPCC, as well as notes on GiveWell’s conversations with climate change experts. Based on these, I’ve come to the tentative conclusion that while climate change is an important issue, it’s unlikely to be the most important issue, though there is uncertainty, owing to poorly understood tail risk.
Potential Impacts according to the IPCC
GiveWell recently wrote up a summary and review of some of the impacts of unmitigated climate change, as described by the Intergovernmental Panel on Climate Change's 2007 Fourth Assessment Report. GiveWell writes:
The most succinct summary of the expected impact is given by a GDP drop estimate:
Such a drop would be highly undesirable, but far from catastrophic. World GDP has been growing at a rate of ~3%, so this corresponds only to a set-back of ~6 years. Poor countries are expected to become richer regardless, and because of marginal diminishing utility, such a setback would carry less negative humanitarian impact than such a setback would if it occurred today.
Overly weak assumptions regarding adaptation?
The IPCC considers what the impacts of climate change will be in 2050; a full 35 years away. My intuition is that over the course of the next 35 years, human society will adapt in such a way that the issues that the IPCC describes will have a smaller negative humanitarian impact than the IPCC suggests. I have not vetted the references given by the IPCC, and may be mistaken about their implicit assumptions, so my remarks should be taken with a grain of salt.
To explicitly address some of the impacts discussed in the IPCC:
There are also more general relevant considerations:
Breakthroughs in genetic engineering, artificial intelligence and whole brain emulation could also radically alter human needs themselves.
The IPCC as overly optimistic?
Some people have voiced the concern that the IPCC is overly optimistic in its predictions of climate change impacts. This is corroborated by the recent paper Climate change prediction: Erring on the side of least drama, which reports that historic IPCC predictions of current impacts of climate change have erred on the overcautious side. But given that the IPCC represents a consensus, barring tail risk, it seems unlikely that the IPCC is overly optimistic by a huge margin.
Tail risk
The biggest reason to be concerned about climate change is that there’s a small probability that the negative impact could be huge.
There is a danger of permafrost in the Arctic melting and releasing methane, creating a feedback loop where the release of methane, global warming, and the melting of the permafrost reinforce each other. This could increase global temperature by 3.5 degrees Celcius, greatly exacerbating all other impacts of climate change. Even if this doesn’t happen, it could be that climate models are wrong, and that the amount by which the earth temperature will rise is much greater than current models predict.
The potential impacts of a much larger increase in temperature than what the IPCC predicts are less studied. One starting point for reading on this is the 4degrees and beyond international climate conference.
About the author: I worked as a research analyst at GiveWell from April 2012 to May 2013. All views expressed here are my own.
Acknowledgements: Thanks to Nick Beckstead, Vipul Naik and Carl Shulman for helpful suggestions.
To be continued: I'll be writing up a follow up report about the implications of the projected impacts for effective philanthropy.