[Alextigtig]

I was also convinced that this was a reasonable way of looking at things because often the "climate change debate" is portrayed as two-sided; one arguing that climate change isn't a big deal and one arguing that it is. This leads to the false supposition that the true answer lies somewhere in the middle, but unfortunately it does not.

For me, one of the most eye-opening experiences was reading an article from the New Yorker the worst of what may happen due to climate change.[0] Because the "climate change is happening" side often tries to ground their claims in research and climate-models, they are rarely apocalyptic or even the slightest bit exaggeratory, while the other side often argues at the opposite extreme of "nothing will happen." I found this article to be helpful in orienting the debate, as it helped me realize that the expected value of doing nothing is really far worse than what I imagined.

[0] http://nymag.com/daily/intelligencer/2017/07/climate-change-...

[eschevarria]

The New York Magazine is not research. Want to know what the actual research says?

Look at figure 10.1 on page 690 of the IPCC’s AR5 WG II report. As it shows, most of the studies on the total impact of climate change for increases between 2.6 and 4.8 °C, which is the range for the IPCC’s highest emissions scenario during the 21st century, result in estimates of the impact on welfare equivalent to a change between 0% and −3% in GNP. Positive effects are included in the estimates, so 0% and two positive values appear outside the range. This is not about the economic impact but about the total impact on welfare, so it really is what is relevant. The factors considered by the studies include variation in agricultural yield, water availability, changes in tourism flow, energy demand, impact on human health, labor productivity.

How bad do you think −3% is during the 21st century? That’s less than 0.035% less economic growth starting in 2014 when the Fifth Assessment Report was published. Even a policy that was completely effective at entirely preventing any global warming could only be justified if its cost was otherwise less than 0.035%. The policies we could implement would not be completely effective and would certainly cost more than 0.035%. Therefore the expected value of doing nothing about global warming is higher than the expected value of doing something.

[Arn_Thor]

An overly simplistic conclusion based on a pick-and-choose approach to the report. First let me quote from the summary just a few pages down: "In sum, estimates of the aggregate economic impact of climate change are relatively small but with a large downside risk. Estimates of the incremental damage per tonne of CO2 emitted vary by two orders of magnitude, with the assumed discount rate the main driver of the differences between estimates. The literature on the impact of climate and climate change on economic growth and development has yet to reach firm conclusions. There is agreement that climate change would slow economic growth, by a little according to some studies and by a lot according to other studies. Different economies will be affected differently. Some studies suggest that climate change may trap more people in poverty."

Note that the literature diverges in its estimation of the impact. Much of the report on the economic impact basically says "there's a lot we don't know about most of these things" because the event haven't taken place yet. But that doesn't mean we can't extrapolate. Economic forces push populations. And, the effects will differ by geography, which is the crucial point. If only coastal areas are affected, that will still incentivize people to make decisions that affect inland economies. And these are the risks that a high proportion of the world's population would face (from the very same report):

The key risks that follow, all of which are identified with high confidence, span sectors and regions. Each of these key risks contributes to one or more reasons for concern [RFC].

i) Risk of death, injury, ill-health, or disrupted livelihoods in low-lying coastal zones and small island developing states and other small islands, due to storm surges, coastal flooding, and sea level rise.37 [RFC 1-5] ii) Risk of severe ill-health and disrupted livelihoods for large urban populations due to inland flooding in some regions.38 [RFC 2 and 3] iii) Systemic risks due to extreme weather events leading to breakdown of infrastructure networks and critical services such as electricity, water supply, and health and emergency services.39 [RFC 2-4] iv) Risk of mortality and morbidity during periods of extreme heat, particularly for vulnerable urban populations and those working outdoors in urban or rural areas.40 [RFC 2 and 3] v) Risk of food insecurity and the breakdown of food systems linked to warming, drought, flooding, and precipitation variability and extremes, particularly for poorer populations in urban and rural settings.41 [RFC 2-4] vi) Risk of loss of rural livelihoods and income due to insufficient access to drinking and irrigation water and reduced agricultural productivity, particularly for farmers and pastoralists with minimal capital in semi-arid regions.42 [RFC 2 and 3] vii) Risk of loss of marine and coastal ecosystems, biodiversity, and the ecosystem goods, functions, and services they provide for coastal livelihoods, especially for fishing communities in the tropics and the Arctic.43 [RFC 1, 2, and 4] viii) Risk of loss of terrestrial and inland water ecosystems, biodiversity, and the ecosystem goods, functions, and services they provide for livelihoods.44 [RFC 1, 3, and 4] Many key risks constitute particular challenges for the least developed countries and vulnerable communities, given their limited ability to cope.

IF you were correct in your assertion that the economic cost of doing nothing is lower than the economic cost of doing something, the ETHICAL cost of doing nothing is immeasurable because we'd willingly be exposing current and future generations to all of the above higher risks.

[b1daly]

Uh, all of these things are happening already, and will continue to happen. The biggest causes of unnecessary misery in this world are political (which of course encompasses the physical environment.)

The questions are what the best course of action would be: for individuals, neighborhoods, states, continents.

We cannot escape the physical environment we live in, and to fantasize that somehow compiling a list of risks could lead to some dramatic action is not illuminating. Taking such talking points out of context is confusing.

[Arn_Thor]

Yes, all of these are happening, and they're going to get worse and affect more people.

This list isn't taken out of context. It's from a detailed report outlining causes and effects, followed by policy recommendations and methods for governments to address each risk as well as mitigate climate change to reduce those risks. (It's also not out of context because I posted it in a comment thread about the effects of climate change [context])

What you're seeking is found in the report I quoted from

[polotics]

This report is from 2014. Since then a few GDP hits happened: Texas, Northeastern seaboard... Excepted value distribution is extremely skewed.