Response of the Arabian Sea to global warming and associated regional climate shift

Abstract

a b s t r a c tThe response of the Arabian Sea to global warming is the disruption in the natural decadal cycle in the sea surface temperature (SST) after 1995, followed by a secular warming. The Arabian Sea is experiencing a regional climate-shift after 1995, which is accompanied by a five fold increase in the occurrence of ''most intense cyclones". Signatures of this climate-shift are also perceptible over the adjacent landmass of India as: (1) progressively warmer winters, and (2) decreased decadal monsoon rainfall. The warmer winters are associated with a 16-fold decrease in the decadal wheat production after 1995, while the decreased decadal rainfall was accompanied by a decline of vegetation cover and increased occurrence of heat spells. We propose that in addition to the oceanic thermal inertia, the upwelling-driven cooling provided a mechanism that offset the CO 2 -driven SST increase in the Arabian Sea until 1995.

Role of Arabian Sea warming on the Indian summer monsoon rainfall in a regional climate model

“…To understand and quantify the role of AS warming on the ISMR, we carry out two idealized sensitivity experiments. In the first experiment, hereinafter referred to as SST0.45, we increase the SST uniformly over the box region (50 E:75 E; 0 N:25 N) shown in Figure 1 by 0.45 C, whereas, in the second experiment, hereinafter referred to as SST0.90, we increase the SST uniformly over the box region by 0.90 C. These values are chosen based on the trend of SST over the AS in the last several decades as reported in different studies (Kumar et al, 2009;Dinesh Kumar et al, 2016;Ratna et al, 2016). The control simulation (CTL) without any SST perturbations is referred to as CTL in the manuscript.…”

Evidence for multiple stressor interactions and effects on coral reefs

“…These reinforcing effects were seen with ultraviolet radiation (Anderson et al, 2001) and pathogen growth (Bally & Garrabou, 2007) and virulence (Banin et al, 2003) as well as fishing (by causing shifts in community structure or abundance; however, the aggregate response of reef fish populations to temperature increases appears to be complex and variable, resulting in changes in physiology, behavior, and recruitment (Lo-Yat et al, 2011;Feary et al, 2010;Gardiner et al, 2010)). Potentially reinforcing effects were seen between increased temperature and cyclone and hurricane frequency (Pielke, 2005;Anthes et al, 2006), and for low-salinity stress (Faxneld et al, 2010), although the former is controversial (Hayne & Chappell, 2001;Hetzinger et al, 2008;Kumar et al, 2009) and there is conflicting evidence of the latter (Porter et al, 1999). Potentially mitigating stressor interactions were seen for crown-of-thorns starfish, which appear to have a relatively narrow temperature tolerance during their larval stage (Johnson & Babcock, 1994), with adult mortality occurring at temperatures of 33-34°C (Yamaguchi, 1974).…”

Recent Acceleration of Arabian Sea Warming Induced by the Atlantic‐Western Pacific Trans‐basin Multidecadal Variability

“…However, the multidecadal warming rate (amount of warming over decades) of AS SST is not constant but varies in time. Furthermore, the warming rate has been reported to be accelerated since the early 1990s, and this causes a climate regime shift (D'Mello & Prasanna Kumar, 2018;Kumar et al, 2009). Furthermore, the warming rate has been reported to be accelerated since the early 1990s, and this causes a climate regime shift (D'Mello & Prasanna Kumar, 2018;Kumar et al, 2009).…”