Bangkok destined to be unliveable? Ominous trend from Netatmo

I am neither a "warmist" or a "denier" as they call those who are inclined to a group ideological approach to the subject of global warming. And I know from paleoclimatic studies that global changes occur naturally and plausibly via contemporary and excess human energy use. But I find reason for worry with the data shown here. Notice the daily high temperatures for the hot season (April and May) do not seem to have increased much if at all over the past 60 years of record from the Don Muang airport. But I have never thought that daily highs are of great significance. after all, Tucson gets a lot hotter in the day.

But look at daily Bangkok low temperature, usually at or about dawn, over the span of the last sixty years. In contrast to maximum daily hot season temperatures which everyone talks about, daily minima are not much recognized as being of importance, though I claim that these daily low numbers represent, at least in the tropics, the best index of thermal stress on human and perhaps other life. The coincidence of high dew point temp, surface sea temp in the Gulf of Thailand, and thermal comfort level through the day really determine the level of discomfort and danger, and these indices follow closely the daily Tmin during the hot season (April and May) in Bangkok. We see here a marked trend for hot season Tmin (only April and May data shown here) with values rarely exceeding 26-27 back in the fifties, but now commonly at 30 or more. Big difference!

As I write, Bangkok residents, Thai and non-Thai, have found conditions barely tolerable in the past few weeks of early May, 2016, many people remarking that it has been "the worst ever". Those of us who have lived through it would not disagree with my claim, backed by theory and experience,  that a daily morning min of about 35 degrees would be intolerable to human life without some kind of air conditioning. So our thinning margin of safety might be said to be half of what it was when I first came to Thailand in the 1960s.

But we should not rush to claim that this is due mostly to greenhouse gasses. Temperatures here and many places are airport temps, and airports have progressively become embedded in hundreds of square miles of mostly concrete, creating the well-understood effect of urban heating. The other morning, with 7 am temps of the pavement of 34 degrees in my neighborhood on Thonglor, you might say we were already having a local doomsday, though the minimum official airport temp for that day did not exceed 31.

How to distinguish between heating from urbanization and from global warming? I think I see away to do that and will make a project of it.