I thought warmer nights were a fingerprint of CO2 induced warming? John Cook has claimed that at least five times on his blog:  The human fingerprint in the daily cycle. It’s also known as Diurnal Temperature Range, and the theory is that extra CO2 keeps us warm all night.

Now Excellent* (Alarmed) Climate System Experts are saying that UHI (Urban Heat Island) effects can cause warmer nights too, at least in the future. (Perhaps this only applies to future-bricks, not past ones — you think?)

City expected to feel heat as it expands

Ben Cubby

Parts of Sydney will be up to 3.7 degrees hotter by the year 2050, as urban expansion spawns ever more asphalt and concrete, new research suggests.

The ”urban heat island effect” – the build-up of heat in built-up areas – will amplify climate change, particularly in the outer fringes of Australian cities, according to University of NSW researchers.

”If you are living near the edge of a city today, you will notice the temperature change, mainly through the minimum temperature change at night,” said Daniel Argueso, the lead author of the study that was prepared at the Centre of Excellence for Climate System Science.

”There is also the fact that urban canyons prevent winds from moving around freely.”

Read more: The Age

The study they refer too is Argueso et al 2013, where models-that-might-work, project how the landscape of Sydney will change and how that will be affected by the climate predicted for Sydney by other models (which don’t work). It’s a dozen assumptions multiplied by a dozen more to tell us what most skeptics could have told them for free. More asphalt, bitumen, bricks and mortar will absorb more heat in the day and release it at night.

Lucky tarmac, brick walls, roads and planes don’t increase temperatures near official thermometers, otherwise we might find a spurious signal pretending to be a “fingerprint” of man-made CO2 when it wasn’t that at all.

When is a fingerprint not a fingerprint, John?

Why no mention of the UHI factor?

REFERENCE

Argueso, D., J. P. Evans, L. Fita, and K. J. Bormann, Accepted: Temperature response to future urbanization and climate change. Climate Dynamics, 1-17.http://dx.doi.org/10.1007/s00382-013-1789-6

link.springer.com/article/10.1007%2Fs00382-013-1789-6

*They work at a Centre of Excellence for Climate System Science. Don’t take that too literally.