ERL Study - New Projections - Up to 3.7C Higher Heatwave Temps In E. US Cities By 2050

[hatrack]

We know by now that climate change is capable of making bad weather events worse. Heat waves will become longer, hotter, more frequent. Droughts will get drier, flood levels higher, freakish storms less freakish in their regularity. But nothing makes this prospect sound quite so scary as some very specific numbers.

So here are some new ones to ponder. This latest data comes from a recent study, published in the journal Environmental Research Letters, which used a high-resolution climate modeling system to project bad news down to an impressively local level, examining what we might see in the 20 largest cities east of the Mississippi come the late 2050s.

By then, researchers from the University of Tennessee at Knoxville have calculated, heat waves in New York City could be 3.58 degrees Celsius hotter in intensity than they are now, with the average one lasting nearly two days longer (these projections are compared to a baseline of climate data between 2001 and 2004). Cleveland has it the worst, with a heat wave temperature increase of 3.71 degrees Celsius, followed by Philadelphia (3.69). The researchers project that heat waves will grow worse particularly across the Northeast and Midwest, bringing the North and South to roughly equal hot-weather fates.

This set of maps from the study shows, on the left, the four-year average of heat wave intensity calculated from 2001-2004 ("intensity" is defined as the average minimum temperature over three consecutive sweltering nights). The middle map shows a three-year average from our projected future climate, in 2057-2059. And the map on the right illustrates the difference between the two (those numbers are degrees Celsius).



EDIT

http://www.theatlanticcities.com/neighborhoods/2012/12/how-bad-will-climate-change-get-eastern-us-look-these-crazy-maps/4208/

[AverageJoe90]

1. Does look pretty plausible under the worst-case BAU scenario......

Are they indeed assuming a 6-7*C temperature rise by 2100, btw?

[joshcryer]

2. Nope, they're looking at localized weather events, using a much more refined model.

Apparently, from the paper itself, they say that there are computational limits to using that level of refinement:

For the CMIP5, present climate simulations and four future climate RCP (RCP 2.6, RCP 4.5, RCP 6.0 and RCP 8.5) scenarios were designed. The present climate simulations with CESM are from 1850 to 2005 and the RCP scenarios are from 2005 to 2100. The analysis of global climate simulations were well documented by Meehl et al [24]. Considering the limited computational resources in this regional high resolution downscaling study, a four year period (2001–4) was selected to represent present climate and one RCP scenario (RCP 8.5 [46]) was used to illustrate future climate conditions from 2057–9. For both present and future climate simulations, one month spin-up period was applied before both modeling periods in order for the model to reach equilibrium, as suggested by previous studies [47, 48]. Among the four RCP scenarios, RCP 8.5 projects the most intensive fossil fuel emissions, which is comparable [24] to the Special Report on Emissions Scenarios (SRES) A1FI [49] scenario.

The reason it's more computationally intensive is because they have a much better topographic model among other things:

The improvement in WRF for heat wave intensity is primarily contributed by more realistic topography, while the improvement for heat wave duration and frequency indicates better skill in regional climate models. Among the states with statistically significant improvement in WRF over CESM, the greatest improvements include: heat wave intensity in Florida (97%), heat wave duration in Maryland (91%) and heat wave frequency in Kentucky (98%). For those states that CESM achieves lower bias than WRF (numbers with negative sign), the performance differences between CESM and WRF are not statistically significant. Thus, by taking advantage of high resolution topography and land use information, dynamical downscaling statistically improves, or at least performs similarly to, CESM for the heat wave reproducing over the eastern US.

This model speaks nothing to the globe, but it should make policy makers in other regions take heed, and run similar models over their regional areas, if we cannot produce a model like this globally because of potential computational limitations.

No matter, it doesn't bode well for the species.

[AverageJoe90]

3. Okay, thank you for clarifying that.

Also, the species itself will be fine. It's civilization we may need to be concerned about in the long run(and perhaps even much of the Third World in the short term, too).

[NoOneMan]

4. Im only concerned insofar as it still burning coal

It's civilization we may need to be concerned about in the long run

I am concerned about civilization in much the same way a doctor is concerned about a patient's cancer.

[AverageJoe90]

5. Well, I dunno if cancer treatment is the best allegory at this juncture.....

But I suppose it'll do. And, btw, not all cancer is fatal if treated correctly(and early enouhgh)......