A progressively wetter early through middle Holocene climate in the eastern lowlands of Guatemala

New estimates of the magnitude of the sea-level jump during the 8.2 ka event

“…Proxy climate records from the Caribbean region (Peros et al, 2017) and Central America (Lachniet et al, 2004) suggest lower precipitation and higher evaporation during the 8.2 ka event, which could have led to increased lake water salinity. Our sedimentological and micropaleontological results, however, indicate rapid expansion and deepening of the lake, and other studies found that regional precipitation in the Lake Izabal catchment increased at that time (Winter et al, 2020;Duarte et al, 2021). Second, the limnological changes could have resulted from marine incursion.…”

Interhemispheric antiphasing of neotropical precipitation during the past millennium

“…This suggests that although there is substantial variability among the Northern records, the general pattern is a transition to a drier climate during the LIA. The coherency among the Southern records is likely at least in part a result of the abundance of PRECIPδ 18 O records [which capture broad, regional-scale processes associated with the SAM ( 7 )] in that group, while the relative heterogeneity among the Northern records is likely due to complex, locally controlled processes related to topography ( 62 ), coastal proximity, and associated atmospheric circulation ( 26 ), as well as the greater diversity of proxy types and the disparities in specific hydroclimate information they record (see Materials and Methods ).…”

“…Rather, they point toward a more complex response characterized by a southward shift in the mean position of the ITCZ coupled with a reduction in strength within the Core region and local climate controls in Central America that, in some locations, appears to predominate over the broad, synoptic-scale influences expected from changes in the ITCZ. In the northern neotropics, several controls add complexity to precipitation dynamics and thus may help to explain differences between the records, including variations in the Atlantic–Pacific cross-basin SST gradient and the resulting shifts in interbasin atmospheric circulation ( 29 ), the direct influence of the Atlantic Warm Pool on precipitation in the Yucatan region during the fall (after the ITCZ has migrated to the south) ( 62 ), and enhanced local rainout during topographic uplift on Caribbean-facing mountains in response to strengthened trade winds (which commonly occur when the ITCZ is shifted southward) ( 71 ).…”

Early Maize in the Maya Area

“…The spread of maize across the Lowlands and some adjacent Highland settings, such as in Honduras and El Salvador, may have corresponded with increases in maize yields that began before 4500 cal BP and that were associated with localized precipitation increases. Widespread regional drying as early as 4,500 years ago (including a globally recorded event about 4200-3900 years ago) may possibly have helped open some Chronology (cal BP) for evidence of early maize between Chiapas, Mexico, and Costa Rica, alongside the precipitation record from Lake Izabal (Duarte et al 2021: Figure 8). Lake Yojoa is not included because of the dating imprecision associated with its record.…”

“…The history of maize in the southeastern sector of the Yucatan Peninsula is more informative. Recent paleoecological work at Lake Izabal (Duarte et al 2021) yielded a sediment core dating back to 9500 cal BP, with maize first appearing by about 4700 BP (Jonathan Obrist-Farner, personal communication 2021). Rue (1989:178–179) reported the first appearance of maize from Lake Yojoa, Honduras, about 125 km east of Copan, above a radiocarbon date in a core of 4770 ± 385 (UGA-5380).…”