Steep topography, a tropical climate, and mafic lithologies contribute to efficient chemical weathering and carbon sequestration in the Southeast Asian islands. Ongoing arc–continent collision between the Sunda-Banda arc system and Australia has increased the area of subaerially exposed land in the region since the mid-Miocene. Concurrently, Earth’s climate has cooled since the Miocene Climatic Optimum, leading to growth of the Antarctic ice sheet and the onset of Northern Hemisphere glaciation. We seek to evaluate the hypothesis that the emergence of the Southeast Asian islands played a significant role in driving this cooling trend through increasing global weatherability. To do so, we have compiled paleoshoreline data and incorporated them into GEOCLIM, which couples a global climate model to a silicate weathering model with spatially resolved lithology. We find that without the increase in area of the Southeast Asian islands over the Neogene, atmospheric pCO₂ would have been significantly higher than preindustrial values, remaining above the levels necessary for initiating Northern Hemisphere ice sheets.

陡峭的地形、热带气候和基性岩性有助于东南亚岛屿的有效化学风化和碳封存。自中新世中期以来，巽他-班达弧系统和澳大利亚之间正在进行的弧-大陆碰撞增加了该地区地表暴露的陆地面积。与此同时，自中新世气候最佳时期以来，地球气候已经变冷，导致南极冰盖的增长和北半球冰川作用的开始。我们试图评估东南亚岛屿的出现通过增加全球耐候性在推动这种降温趋势方面发挥了重要作用的假设。为此，我们编制了古海岸线数据并将其纳入 GEOCLIM，它将全球气候模型与具有空间分辨岩性的硅酸盐风化模型相结合。我们发现，在新近纪上不增加东南亚岛屿面积的情况下，大气p CO ₂将显着高于工业化前的值，仍高于形成北半球冰盖所需的水平。