John Latham and Alan Gadian

Coral Bleaching (in preparation)

Hurricane amelioration

Meridional Heat flux

1

2

3

Table 1. Changes in sea surface temperatures between the three experiments described in Section 3.1, all values in K. The three regions, Caribbean, Great Barrier Reef and Polynesia are shown in black rectangles in Figure 1.

Region 2xCO2 – Control 2xCO2+MCB – ControlGlobal 0.67 –0.12Caribbean 0.53 –0.04Great Barrier Reef 0.55 0.13Polynesia 0.64 –0.58

[NB: 2xCO2+ All Clouds MCB – Control: Global temperature change -6.5 K]

4

Table 2. The number of mild and severe bleaching events over a 20-year period for the three simulations: Control, 2xCO2, and 2xCO2+MCB. Bleaching events are calculated based on two heat-stress thresholds: 1°C above the climatological maximum, and 2.45 x SDmax above the climatological maximum. Climatological maxima were calculated based on the Control. Note that the Control provides the background number of bleaching events expected under normal conditions. Number in parentheses are the number of ocean cells within each reef region.

Control 2xCO2 2xCO2+MCB

Region Mild Severe Mild Severe Mild SevereCaribbean (439)1°C 0 0 294 104 0 02.45 SDmax 0 0 655 177 3 0

Great Barrier Reef (179)

1°C 0 0 323 71 0 02.45 SDmax 0 0 311 36 0 0

French Polynesia (899)

1°C 95 2 1056 1884 32 02.45 SDmax 3 0 850 1502 2 0

5

Controlled Hurricane Weakening via Marine Cloud Brightening

Figure 1. Sea surface temperature (SST) differences (oC) between conditions 2xCO2

and 1xCO2, within an area bounded by

latitudes 30 degrees North & 30 degrees S and longitudes 110 degrees West and 60 degrees East. There is no seeding. The inner, dashed rectangle defines the hurricane development region HDR. The average difference in SST (from Control) is 0.66oC in the HDR and 0.53oC globally.

Figure 2. SST differences between patchy seeding at 2xCO2 and Control (1xCO2, no seeding). The average difference in SST (from Control) is 0.13oC in the HDR and -0.11oC globally

6

Figure 3. SST differences between full seeding at 2xCO2 and Control (1xCO2, no seeding). The average difference in SST (from Control) is -4.0oC in the HDR and -5.04oC globally

Figure 4. SST differences between full seeding at 1xCO2 and Control (1xCO2, no seeding). The average reduction in SST produced by seeding is -4.6oC in the HDR and -5.38oC globally

7

Controlled Hurricane Weakening via Marine Cloud Brightening

See poster

Figure CO2 Seed HDR Global

1 x2 None 0.66 0.53 2 x2 3*Patch 0.13 -0.11 3 x2 Full -4.00 -5.04 4 x1 Full -4.61 -5.38

Table 1. Departures (oC) of average Sea Surface Temperature (SST) values from Control (no seeding, 1xCO2) for the four figures (Fig. 1-4 )

presented below. Seed is the type of seeding, HDR is the Hurricane Development Region (defined in the text), and the atmospheric CO2

concentration is either the current value (Control) or twice the pre-industrial value.

8

Meridional Heat Flux

----

see poster

Figure 1 Plots of the radiative balance and MHF in Wunsch (2005) and values from the HadGEM1 climate model. (Martin et al, 2006)

Figure 3. Plot showing the MHF for four geoengineering simulations in HadGEM1.

9

10