high-resolution paleoclimate record from SE Iran reveals extreme sensitivity of West Asia to temperature changes since the Little Ice Age

The dearth of high-resolution climate records for the past millennium has largely limited ourunderstanding of the impacts of natural (e.g., the Little Ice Age: LIA) and anthropogenic climateperturbations (i.e., the ongoing global warming) on the arid regions of West Asia (also referred to as theMiddle East). Here, we present multiproxy records including compound-specific δ13C signature of leafwax-derived n-alkanes (δ13Cn-C29), elemental and mineralogical compositions, total organic andinorganic carbon contents, C/N ratio, biogenic silica content and magnetic susceptibility of a 550 cm-longlacustrine sediment core retrieved from Sardarya Lake, SE Iran, spanning the period 1450-2017 AD. In ourarchive, n-alkane C29 is the dominant homologue and primarily derived from Artemisia herba-albashrubs—a C3 plant prevailing on the slopes overlooking the lake. Compound-specific δ13Cn-C29 valuesfluctuate in the range of C3 plants (-29.4 to -32.1‰ VPDB) with enriched (depleted) values correspondingto episodes of decreased (increased) lake levels reconstructed using the Rb/Sr ratio, as well as with thesignificant presence of evaporitic minerals such as aragonite, gypsum and calcite, corroborating theapplicability of δ13Cn-C29 as a proxy for plant water use efficiency (i.e., water stress). Our proxy datareveal three distinct climate intervals: (I) arid LIA (1450-1830 AD), (II) wet post-LIA (1830-1990 AD), and(III) arid recent decades (1990-2017 AD). The increased climate aridity during the LIA shows a link to thedecrease in solar activity with the driest conditions being synchronous with the Maunder Minimum (1645-1715 AD), which is thought to be the coldest part of the LIA. On the contrary, the recent dry decades, whichappear as severe as those during the LIA, coincide with the climax of human-caused global warming. Thus,our findings reveal an extreme sensitivity and vulnerability of the arid regions of West Asia to rather smallnatural and anthropogenic temperature changes. This highlights the need for forward-lookingcollaborative policies to mitigate future impacts of the ongoing global warming and to lessen the risk ofdroughts as a potential exacerbating factor for social upheavals in West Asia.

کلیدواژه های high-resolution paleoclimate record from SE Iran reveals extreme sensitivity of West Asia to temperature changes since the Little Ice Age:

Drought ، Global warming ، Lake level ، Leaf-wax n-alkanes ، Little Ice Age ، Rb/Sr ratio ، SE Iran