An intensification of the hydrological cycle is an expected consequence of global warming, and this will likely lead to spatially variable precipitation and drought extremes, and more intense tropical storms. Deep time hyperthermal events, characterised by large-scale carbon release and transient global warming, have the potential to provide insights into the nature and magnitude of hydroclimate changes in response to warming. The Toarcian oceanic anoxic event (T-OAE, or Jenkyns Event, ∼183 Ma) was a severe hyperthermal, and is associated with evidence for marked changes in hydroclimate, including: intensified tropical cyclone activity, an increase in global chemical weathering rates, and elevated freshwater runoff and terrigenous sediment fluxes to basins. Nevertheless, key knowledge gaps exist regarding the scale, significance, distribution and interpretation of these changes. Here, we review the evidence for T-OAE hydroclimate changes based on published data from 109 sites. Although these sites are primarily concentrated in the northwest Tethys region, we show that evidence for T-OAE hydroclimate change was globally distributed, and that most sites (63 %) record evidence consistent with an intensification of hydrological cycling under hotter conditions likely characterised by weather/precipitation extremes. Evidence for enhanced storm activity is common; recorded at up to a third of sites from both low and middle latitudes. This evidence is consistent with climate model predictions of increased tropical cyclone intensity and a poleward shift in storm tracks under elevated atmospheric CO2. Evidence for enhanced weathering and terrigenous fluxes is also common. This evidence, coupled with the evidence for increased storminess, may help explain increased turbidite deposition during the event recorded at some deep-water sites. Although affected by geographic and perhaps sedimentological biases, our findings underline how hydroclimate change was an inherent and perhaps defining characteristic of the T-OAE, potentially of equal paleoenvironmental significance to the seawater deoxygenation that originally defined the event.

中文翻译：

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Toarcian 海洋缺氧事件期间的全球水文气候扰动


水文循环的加剧是全球变暖的预期结果，这可能导致空间变化的降水和极端干旱，以及更强烈的热带风暴。以大规模碳释放和瞬态全球变暖为特征的深时高温事件有可能提供对响应变暖的水文气候变化的性质和幅度的见解。Toarcian 海洋缺氧事件（T-OAE，或 Jenkyns 事件，∼183 马）是一种严重的高温事件，与水文气候显着变化的证据有关，包括：热带气旋活动的增强，全球化学风化速率的增加，以及淡水径流和流域陆源沉积物通量的增加。然而，关于这些变化的规模、意义、分布和解释，存在关键知识差距。在这里，我们根据来自 109 个地点的已发布数据回顾了 T-OAE 水文气候变化的证据。尽管这些地点主要集中在特提斯西北部地区，但我们表明 T-OAE 水文气候变化的证据在全球范围内分布，并且大多数地点 （63%） 记录的证据与在可能以极端天气/降水为特征的较热条件下水文循环的加强一致。风暴活动增强的证据很常见;在多达三分之一的低纬度和中纬度地点都有记录。这一证据与气候模型预测的热带气旋强度增加和大气 CO2 升高下风暴路径向极地移动的预测一致。风化和陆源通量增强的证据也很常见。 这一证据，再加上暴风雨增加的证据，可能有助于解释在一些深水地点记录的事件期间浊积增加。尽管受到地理和沉积学偏差的影响，但我们的研究结果强调了水文气候变化是 T-OAE 的固有特征，也许是决定性的特征，可能与最初定义该事件的海水脱氧具有同等的古环境意义。