Ocean acidification may be increasing the intensity of lightning over the oceans

Abstract

The anthropogenic increase in atmospheric CO2 is not only considered to drive global warming, but also ocean acidification. Previous studies have shown that acidification will affect many aspects of biogenic carbon uptake and release in the surface water of the oceans. In this report we present a potential novel impact of acidification on the flash intensity of lightning discharged into the oceans. Our experimental results show that a decrease in ocean pH corresponding to the predicted increase in atmospheric CO2 according to the IPCC RCP 8.5 worst case emission scenario, may increase the intensity of lightning discharged into seawater by approximately 30 ± 7% by the end of the twenty-first century relative to 2000.

The Potential Effect of Anthropogenic Salinization and Ocean Acidification on Lightning Flash Intensity Over the Mediterranean Sea

“…The multivariate linear fit model of LFI as a function the experimental conditions of salinity, pH and TA, yields significant fits for pH and TA and non-significant for salinity (Figure 2). Furthermore, the leverage residuals for LFI indicate a significant positive relation with TA as expected [14], a significant negative relation of LFI with pH as expected [13] and an unexpected negative yet insignificant relation with salinity [12]. It should be noted that in the Asfur [12] study, the dependence of LFI on salinity was established for a NaCl solutions with increasing concentration (0-7 g/L).…”

“…These conclusions were based on laboratory generated electrical sparks that were discharged into the experimental solutions as detailed in the methods section below. Based on these experiments it was shown that the Lightning Flash Intensity (LFI) in our experimental setup, is positively correlated with the concentration of NaCl in de-ionized water solutions [12], negatively correlated with the pH and positively correlated with the TA of LS seawater of [13,14]. The salinization and corresponding increase in TA due to the AHD and increased evaporation due to global warming, coupled with the ongoing process of OA in the LS could have caused lightning intensity in this region to increase.…”

“…This rate is slightly higher than the rate of acidification in oceanic surface waters due to the anthropogenic increase in atmospheric CO 2 [10,11]. In our previous studies we showed that the intensity of lightning discharged into the oceans may be influenced by the salinity, pH and TA of the receiving sea surface water [12,13] and Silverman [14]. In these studies we suggested that the apparently high density of superbolt activity [15] in the Mediterranean Sea (ca.…”

“…LFI measurements were performed using the same experimental setup described by Asfur and Silverman [12][13][14]. However, in this study we report the integrated value of LFI over the entire spectral range (150-900 nm) in µW•cm -2 following factory calibration.…”

“…Accordingly, the resulting increase in total alkalinity (TA) according to Bialik & Sisma-Ventura [9] during the wintertime over the same period was 2594-2596 to 2616-2635 µmol•kg -1 (ΔTA = 41 µmol•kg -1 ). Based on a reconstructed record of DIC in LS seawater from measurements of δ 13 C in eastern Mediterranean Vermetid reef cores, estimated TAs (from salinity), they calculated the change in pH over the same period, which yielded an overall decrease in the pH of LSW from ~8.1 to ~8 at a rate of -0.022 ± 0.002 decade -1 . This rate is slightly higher than the rate of acidification in oceanic surface waters due to the anthropogenic increase in atmospheric CO 2 [10,11].…”