Strange how most of the darker colored regions on the map, those most likely to be impacted by the combination of heat and humidity, generally centered around the equator, are also those with the highest birth rates. The NYT is for some reason loathe to mention overpopulation in almost all of these articles centered around climate change. 8 billion is too many people for the 3rd rock from the sun, and it's projected to be around 11 billion by mid-century. The numbers might be curtailed by dwindling resources, dying oceans, and wars over water and food supplies. In any event, those most severely impacted will be the elderly, those with pre-existing medical conditions, and the youngest. That's how it works with Mother Nature in the animal kingdom. Those are the ones that struggle when food is scarce- the young and elderly and physically compromised can't hunt their prey or outrun their predators. We're just animals that walk upright with supposedly bigger brains. Those bigger brains aren't necessarily better though, humans are the cause of the coming calamities. Pogo was right. So was that native American chief who said one day when all the food is gone along with the clean water and clean air, the rich will finally discover that you can't eat, drink, or breathe your money. You can't even take it with you.

The issue of the dangerous heat and humidity combination is well presented, i.e. scientifically without exaggeration about dangers or underplaying them. Together with the consequences of the IPCC’s Fifth Assessment Report humanity has to make really drastic systemic personal lifetime changes. One pathway for doing this is transforming the unjust, unsustainable, therefore, unstable international monetary system by adopting a carbon standard of a specific tonnage of CO2 per person. The conceptual, institutional, ethical and strategic dimensions of such system with its carbon reduction system of a Hansen/McKibben model of fee and dividend are presented in Verhagen 2012 "The Tierra Solution: Resolving the climate crisis through monetary transformation" and updated at www.timun.net. Outstanding economist and climate advocate Bill McKibben stated about this Tierra Fee and Dividend system: “The further into the global warming area we go, the more physics and politics narrows our possible paths of action. Here’s a very cogent and well-argued account of one of the remaining possibilities.”

I saw, but did not read, this article this morning on my digital homepage. In the afternoon, I had to use the NYT search to find the article. Why? This is an article of interest to us all.

What in this reporting is "opinion"?

Read the fine print. These are predictions making certain (pessimistic) assumptions about greenhouse gas emissions and climate sensitivity. Not only are temperature predictions uncertain, but almost no attention has been paid to the validity of humidity predictions that are essential but likely equally uncertain. Also note that "heat index" does not directly map onto wet bulb temperature (the actual physical variable). And "weather station data...do not match model-estimated historical heat indices"; in other words, where the models have been tested, they have got it wrong. Societies in hot climates adapt by deferring outside work to the morning and evening (the siesta of Spanish and Mediterranean cultures), by building structures of adobe that average the daily temperature cycle, being warm at night and cool in the hottest part of the day... Don't panic.

Virtually everyone in Phoenix has air conditioning. And when outside, virtually everyone carries water. But there is one huge problem. There are a good number of folks who can't afford to run their air conditioners during the summer. And while there is a subsidy program, it is ridiculously underfunded -- only 3.5% receive benefits. Air conditioning in Phoenix is like heating up north. If it isn't available, you've got a life threatening crisis.

Thanks Republicans.

"None like it hot."

More non stop good news, from The New York Times! Obviously, we are all doomed probably earlier than we think!!!

We all complain, analyst, think and look at those science sophisticated datas, but remember every time you consume things or do these things in this americanize society, you already contribute to make our climate change to the worse • Eat take out or call for food delivery (things like this don't really exist in many part of the world, hard to find food delivery in major European cities or Asia, except pizza) • Recently IKEA cafeteria in Brooklyn doesn't use real plates, cups and silver utensils anymore, when the concept of the affordable cafeteria comes with being sustainable in both food and how you serve it, the cafeteria design also has place to put dirty dishes. Lazy staff and customers. • Parties both for kids and adults using loads of plastic utensils, paper plates (what's wrong with your dishwashers). • Those online services with loads of shipping in boxes back and fourth (online clothing rental subscription), Preset meals delivery just because you want to cook and can't bring recipes to shop at supermarket anymore. To be fair, this kind of wanna be chef services are more in the metro areas, not in the remote country side. • Shopping in supermarkets using loads of plastic bags instead of bringing your own reuse bags. • Anti-bike lanes people in NY who obviously wouldn't want to bike or take publics. They exist, with lame excuses just because they want to drive and bike lanes take parking spots away! And you wonder why climate change get worse, without doing a thing..

As the middle class rapidly expands by millions in countries like China and India, the first thing they want or need is air conditioning and a car. This will most certainly seal the deal or tipping point of no return. Along with the northern tundra thawing and releasing massive amounts of methane gas. Things are not looking too good for our spaceship earth.

i guess i serve as a canary in the coal mine. i have residual R hemiparesis and attendant severe nerve damage, both of which caused my biofeedback doctor 30 years ago to declare me a 'human barometer'. fast forward to this past summer, and even today with mild temps and impending rain, wherein i lost approximately 4 months to my body over-ruling my mind. yes, i forewent a/c for the enviroment, ridiculous costs, and maintenance.

It is ironic - the areas with the higher average temperatures are also areas with the greatest population growth.

I agree with others: why is this in the opinion section? This is not an opinion, this is a report on our best projections of climate change. This is also an under-appreciated impact of global warming that deserves more coverage. The very fact that whole swaths of the Tropics could become barely livable because of near-lethal or outright-lethal heat waves is kind of ...I don't know, mind-boggling. One thing that is missing in this report, though. is under what socio-economic scenario these projections are made. I suspect these are for a business-as-usual scenario (which hopefully we can avoid, at least in part). If that's the case, then one thing to keep in mind is that warming (and "humidifying") under that scenario doesn't magically stop in 2080 or 2100: it actually continues, slowly, all the way to 2200 or 2300...

Heat and Humidity Are a Killer Combination Not if you grow corn. It will grow more than an inch - a day

Another downside or danger is the large uptick of skin cancers. It is growing quickly all over the world. If you have not already, get a screening by a doctor. I demanded one and ended up with having several spots that tested positive and then had them surgically removed. If you wait too long, it can be fatal.

I had heat exhaustion last summer just once. I live in London, where heat is not as extreme as in a lot of parts and cities in the USA, but I do take medication for heart conditions, diabetes, high blood pressure and also some neuroleptics. Half of my medication bottles warn "avoid hot and humid places." I carry now a bottle. An ordinary plastic bottle. When I get hot, I use the simple Hungarian A/C method: I fill the bottle with cold water, and pour it on top of my head, letting it flow to all directions onto my body below. Works wonders. I believe I will see the day when I wake up one morning and see myself get so immensely hot, from one moment to the next, that I will cry in pain, then get parched on the outside, and finally burst into a fluff of smoke like a moth that flies into a flame. I say it will be that rapid, because I firmly believe -- and this is a belief, without supporting evidence, so it's like a religion -- that the Earth's warming is due to astrophysical changes, not due or entirely due to some guilty habit by humanity such as burning fossil fuels.

This is why the entire population of the central band of the earth is trying to get to the northern band (which has more land than the Southern Hemisphere). Migration northward will only get worse.

I don't know why you and other media don't use dew points. When the dew point is near the temperature, moisture does not evaporate from the skin with the resulting problems detailed in the article. When weather forecasts and reports show dew point maps and data, viewers can easily understand and predict how uncomfortable they will be. When the temperature is 90F and the dew point is in the 50s, you can cool off in the shade, but if the dew point is 80, which occurs regularly in the tropics, you are into the danger zone where even the shade provides no cooling. Relative humidity changes throughout the day as the temperature changes. Dew points incorporate air pressure and remain constant even when the temp changes through the day. Weather forecasts in some areas and on some weather websites list the dew point. You can predict just how uncomfortable you will be no matter what the temperature is.

"Questions about how wildlife and natural ecosystems will be affected by humid heat are also mostly unexplored." Great job, sticking this sentence in at the very end of the article. Couldn't one of you have spent 15 minutes to explore it?

I have suffered from heat exhaustion, from a strenuous bike ride on a hot day but no where near as hot as those the article forecasts. It's a dangerous condition and doesn't go away on it's own. Hydration is not sufficient--in fact it can be counterproductive. Quite often, hyponatremia, the depletion of electrolytes, is more critical. Don't be fooled by sports drinks that promise to restore electrolytes; it really can't be done on the fly. The best course is to get to a cool place where a doc can stick an IV into your arm. Failing that, chicken soup and rest can't hurt. Heat exhaustion is just the first stage. Heat stroke is far more dangerous. But on some level, I must wonder whether efforts to preserve life are just delaying the inevitable. Those that suffer from heat exhaustion this year must realize that heat indices aren't going to get any better next year.

It is curious that this is published in the Opinion section. It is based on best projections of climate change, which is more factually based than many opinion pieces. That being said, the projections are very concerning, and emphasize the need for real action. This means pressure from the people on our leaders, as despite 30 years of concern, give or take, little has been done so far. We do, most likely, have the technology and ability to make the necessary changes, but it will take effort and work. ( I suspect if our budget for research, technological improvement, and infrastructure improvement was 1/3 the money spent on the military over the last 20 years, we would be MUCH farther along at this point.)

Good article, and ties in with other studies that point out that these conditions will lead to economic damages due to lost productivity in areas affected. Moving work to nighttime might mitigate a little bit, but a big factor in the deaths here in Chicago was that nights didn't cool enough for the victims, mostly elderly, to recover from the stress of daytime peaks. We were far below the simply-lethal level, but at lower levels, recovery time is necessary - either AC or cool nights, in heatwaves. So Chicago now has cooling centers and does wellness checks to deal with it happening again, but working to prevent the cause of the event has to be the biggest part of the solution, because it doesn't just affect humans. It affects large mammals. "On July 31, 2015 in Bandar Mahshahr, Iran, the heat index reached 165 degrees, among the highest ever recorded. [...] residents were able to take refuge in air-conditioned buildings, middle-class luxuries that don't exist for many in the hottest regions." These luxuries also don't exist for livestock and wild mammals. During prior times when greenhouse concentrations led to much higher temperatures, large animals did OK - dinosaurs, crocodilians, reptiles. Large mammals couldn't survive those conditions then, and won't in the future. So we face a risk of seeing all large mammals, even healthy ones, die in areas affected by just a day or two of extreme conditions that business as usual will drive towards possibility.

Another climate change article silent about the impact of population growth on global warming.

It was a weird summer in central Oklahoma this year. Usually we hit at 100 degrees, sometimes as often as 30 days. This summer was much cooler, rarely getting above 90. Here's the weird thing. It was so humid as to be miserable. Clothes were just soaked in sweat. Eighty-five degrees in this humidity felt more uncomfortable than 100 when it was dry. Sweat just did not evaporate. It felt like working in a steam bath.

Thank you, NYT, for continuing to print stories about the catastrophe we are all facing. Maybe, just maybe, the significance of it will sink in to those in power and those who can do something serious about it. I cannot wrap my head around how people such as the Kochs and others who make money from fossil fuels cannot see how this affects everyone, including them and theirs.

I wonder how much thought has been given to things like transportation. I'm a pilot, and piston airplanes would have a tough time in such weather, as would anything with a turbine engine in it.