If you want to scare people you can tell them that Phytoplankton is sensitive to ocean warming and has been declining over the last century [1] (and the situation has not improved since 2010 [2]). On land, plants don't really like global heating either [3]. Together these effects directly threaten not only the food chain, but oxygen supply itself.

[1] https://www.nature.com/articles/nature09268

[2] https://www.cbc.ca/news/canada/newfoundland-labrador/ocean-p...

[3] https://journals.plos.org/plosbiology/article?id=10.1371/jou...

That's a prime example of what I'm talking about - vague statements ("sensitive", "decline", "threaten") about global effects on complex systems ("the food chain").

What is the expected specific, immediate, local effect of that? Can you tell a particular person (the abovementioned Midwest farmer) some particular clear consequence of phytoplankton decline he's going to personally experience in his lifetime (say, 2070) or the lifetime of his kids (say, 2100) if he doesn't do the utmost to prevent climate change change ?

The articles you quoted make no really scary (to the target audience) claims whatsoever. The third includes an expected impact on agriculture (https://journals.plos.org/plosbiology/article/figure/image?d...) which shows neutral or even positive effects on agriculture in much of first world (and horrible effects on Brasil and SE Asia, but that's not relevant to the USA consumer whom we're asking to change habits).

Timely data is available for the US. The fourth National Climate Assessment just released its report on impacts last month (https://nca2018.globalchange.gov).

This “impacts” report is based on the science NCA report from last year, so if you want the science drivers, see that one. For the first time, both reports are highly regionally decomposed (again, across the US).

One example if you want alarming:

“Recent economic analysis finds that under a higher scenario (RCP8.5), it is likely (a 66% probability, which corresponds to the Intermediate-Low to Intermediate sea level rise scenarios) that between $66 billion and $106 billion worth of real estate will be below sea level by 2050; and $238 billion to $507 billion, by 2100.” (https://nca2018.globalchange.gov/chapter/8/)

The report has much, much more.

The report doesn't seem that scary, actually. The sections on particular impacts list reasonable mitigation actions (that don't have the tragedy of commons problem that climate change prevention does); and the particular impact of sea level rise you quote isn't that large or scary - the listed uncertain, faraway damage is much smaller than the certain, immediate cost of CO2 reduction we'd want. It's large enough to motivate local politicians to plan for mitigation activities - since no matter what they do (and in the absence of global coordination) they'll still be needed, we'll face some global warming and sea level rise even in the most optimistic scenario; but losing 2% of national real estate value over 80 years isn't economic justification for, say, meaningful reduction of consumption; sacrificing 0.1% GDP growth per year (which isn't nearly enough to combat climate change) is a much, much larger cost than the $500 billion tag.

As I skim it, nothing in that report has anything to convince people that "we're all going to horribly suffer if we don't act NOW". Yes, the effects are bad, but any personal impact I can derive from the descriptions in that report are on the same scale as the affected people would see in any major economic downturn.

The regional chapters in particular seem to have very little alarming content; it seems to center on "yep, this area is slowly to get worse, so we need extra infrastructure and preparation" - the described effects sound like sufficient justification for an 1% tax rate hike and doubling of insurance premiums, but not sufficient justification to mandate serious lifestyle change to try and prevent the consequences.

For me, the prospect of $500B costs in just one sector (coastal property damage), which will be in effect transferred to the major stockholders in oil/coal companies, is maddening.

If the prospect of $500B costs until 2100 ($6B/year) in the future seems maddening, then what would people say about an immediate cost of more than $1000B/year, which is what the expected costs of rapid greenhouse reductions (https://www.technologyreview.com/s/527196/how-much-will-it-c... , $13T until 2030 recent estimate) would be, which wouldn't still prevent much of that sea level rise and coastal property damage?

A long-term disaster that needs massive short-term action to avert is really kind of a perfect storm for killing humanity.

You are absolutely right that the discussion needs to be far heavier on what the concrete consequences will be, not in abstract numbers, but in how it will actually affect the lives of their children and grandchildren.

The messaging needs to be ubiquitous. Climate change should be the main topic every single damn day.