Zonally contrasting shifts of the tropical rain belt in response to climate change

Abstract

Future changes in the position of the intertropical convergence zone (ITCZ; a narrow band of heavy precipitation in the tropics) with climate change could affect the livelihood and food security of billions of people. Although models predict a future narrowing of the ITCZ, uncertainties remain large regarding its future position, with most past work focusing on zonal-mean shifts. Here we use projections from 27 state-of-the-art (CMIP6) climate models and document a robust zonally-varying ITCZ response to the SSP3-7.0 scenario by 2100, with a northward shift over eastern Africa and the Indian Ocean, and a southward shift in the eastern Pacific and Atlantic Oceans. The zonally-varying response is consistent with changes in the divergent atmospheric energy transport, and sector-mean shifts of the energy flux equator. Our analysis provides insight about mechanisms influencing the future position of the tropical rainbelt, and may allow for more robust projections of climate change impacts.

Weakened Interannual Variability in the Tropical Atlantic

“…The CMIP6 MMM also shows a significant positive trend of 0.010°year −1 that is represented by 46% of the models (17/37). It is consistent with the increased SST positive trend over the Northern Hemisphere that serves as an attractor for the ITCZ shift to the warmer region (Schneider et al, 2014;Mamalakis et al, 2021). The ITCZ northward trend explains the observed positive trend in the precipitation over the Sahel (Fig.…”

Impacts of climate changes on risk zoning for cowpea in the Amazonian tropical conditions

“…Although an increase of total rainfall during the rainy season is expected for this region, studies indicate a possible change of the position of the ITCZ as a consequence of climate changes. A southward shift during May-October and a shift towards the Equator between November and April (Mamalakis et al 2021) could minimize the scenarios of high climate risk expected for the near future based solely on the results of the RegCM4 model, primarily in the dry season.…”

A storyline view of the projected role of remote drivers on summer air stagnation in Europe and the United States

“…On the other hand, the warming (and spread) over the North Pacific is only slightly higher than GW. This occurs because land areas warm faster than oceans, although the North Pacific is among the oceanic regions that will experience the highest increase in SSTs (Lauvset et al 2017, Mamalakis et al 2021). Conversely, the projected warming over the North Atlantic is considerably lower (albeit more uncertain) than GW.…”