Information on past climates is of primary relevance to archaeology because of what it tells us about the effects on the land and on the resources that people needed to survive. The most crucial effect of climate was on the sheer quantity of land available in each period, measurable by studying ancient coastlines. These have changed constantly through time, even in relatively recent periods, as can be seen from the Neolithic stone circle of Er Lannic, in Brittany, France (once inland but now half submerged on an island) or medieval villages in east Yorkshire, England, that have tumbled into the sea in the last few centuries as the North Sea gnaws its way westward and erodes the cliffs. Conversely, silts deposited by rivers sometimes push the sea farther back, creating new land, as at Ephesus in western Turkey, a port on the coast in Roman times but today some five kilometers inland.

Nevertheless, for archeologists concerned with the long periods of time of the Paleolithic period there are variations in coastlines of much greater magnitude to consider. The expansion and contraction of the continental glaciers caused huge and uneven rises and falls in sea levels worldwide. When the ice sheets grew, the sea level would drop as water became locked up in the glaciers; when the ice melted, the sea level would rise again. Falls in sea level often exposed a number of important land bridges, such as those linking Alaska to northeast Asia and Britain to northwest Europe, a phenomenon with far-reaching effects not only on human colonization of the globe but also on the environment as a whole - the flora and fauna of isolated or insular areas were radically and often irreversibly affected. Between Alaska and Asia today lies the Bering Strait, which is so shallow that a fall in sea level of only four meters would turn it into a land bridge. When the ice sheets were at their greatest extent some 18,000 years ago (the glacier maximum), it is thought that the fall was about 120 meters, which therefore created not merely a bridge but a vast plain,1,000 kilometers from the north to the south, which has been called Beringia. The existence of Beringia (and the extent to which it could have supported human life) is one of the crucial pieces of evidence in the continuing debate about the likely route and date of human colonization of the New World.

The assessment of past rises and falls in sea level requires study of submerged land surfaces off the coast and of raised or elevated beaches on land. Raised beaches are remnants of former coastlines at higher levels relative to the present shoreline and visible, for instance, along the Californian coast north of San Francisco. The height of a raised beach above the present shoreline, however, does not generally give a straightforward indication of the height of a former sea level. In the majority of cases, the beaches lie at a higher level because the land has been raised up through isostatic uplift or tectonic movement. Isostatic uplift of the land occurs when the weight of ice is removed as temperatures rise, as at the end of an ice age; it has affected coastlines, for example, in Scandinavia, Scotland, Alaska, and Newfoundland during the postglacial period. Tectonic movements involve displacements in the plates that make up Earth’s crust. Middle and Late Pleistocene raised beaches in the Mediterranean are one instance of such movements.

Raised beaches often consist of areas of sand, pebbles, or dunes, sometimes containing seashells or piles of debris comprising shells and bones of marine animals used by humans. In Tokyo Bay, for example, shell mounds of the Jomon period (about 10,000 to 300 B.C.E.)mark the position of the shoreline at a time of maximum inundation by the sea (6,500-5,500 years ago),when, through tectonic movement, the sea was three to five meters higher in relation to the contemporary landmass of Japan than at present. Analysis of the shells themselves has confirmed the changes in marine topography, for it is only during the maximum phase that subtropical species of mollusc are present, indicating a higher water temperature.

过去气候的信息主要和考古学相关，因为它使我们认识到气候对陆地以及人们生存所需的资源的影响。气候最为重要的影响在于每一个时代可用土地的明确面积，这一点可以通过研究古代的海岸线来测量。随着时间的推移，甚至是在相对较近的时期，大陆面积在不断变化。法国布列塔尼Er Lannic岛的新石器时代巨石阵（曾经位于内陆而今在一座岛上且被淹没了一半），或者是英国约克郡东部的中世纪村庄（随着北海不断向西扩展，侵蚀海岸，这些村庄在最近的几个世纪里慢慢被海水吞没），都可以看出这一点。反之，是河流堆积的泥沙有时会把海岸线往后推，创造出新陆地，正如在土耳其西部的以佛所，在罗马时期曾经是沿岸的一个港口，而现在则位于距海岸大约5公里的内陆。 虽然如此，对于关注旧石器时期各个长时间段的考古学家来说，海岸线变化有更重要的意义需要思考。大陆冰川的扩张和收缩造成了世界范围内海平面巨大且不规则的上升和下降。冰盖扩大时，海平面因水被储存在冰川中而下降；冰盖融化时，海平面又再次上升。海平面的下降经常会使得许多重要的大陆桥显露出来，比如连接阿拉斯加和亚洲的大陆桥，连接大不列颠和欧洲西北部的大陆桥。这种现象不仅对人类的全球殖民化有着深远影响，对整个环境也一样——对位于封闭区域或海岛上的动植物的影响是根本性的而且通常是不可逆的。阿拉斯加和亚洲之间的白令海峡，非常狭窄，以至于海平面仅仅降低4米就会把它变为一座大陆桥。大约1万8000年前（盛冰期），冰盖扩张到极致，据说海平面下降了120米，因此产生的不只是一座桥而是一块巨大的平原。平原南北相距1000千米，被称为白令陆桥。白令陆桥的存在（以及它可供人类生存的承载量）是与人类定居新世界的路径和时间相关的持续争论的决定性证据之一。 评估过去的海平面上升和下降需要研究沿海被淹没的陆地表面和陆地上的海滩高地。海滩高地就是海平面更高时（与目前高度相比）海岸线的残迹，非常明显，例如旧金山北部加利福尼亚海岸沿线。但是一个位于当前海岸线之上的海滩高地，其高度通常并不能直接代表它之前海平面的高度。大多数情况下，这些海滩的位置更高是因为大陆被地壳均匀的浮升力或构造运动所抬起。当冰川的重量随着气温的升高而消失时，正如一个冰川期的末期，地壳均匀的浮升力就出现了。它会对海岸线造成影响，比如冰后期的斯堪的纳维亚、苏格兰、阿拉斯加和纽芬兰。构造运动包含组成地壳的平面的移动，更新世中晚期地中海区域的海滩高地就是这种运动的实例。 海滩高地通常由包含沙子、鹅卵石的区域或者沙丘构成，有时还会有贝壳，或者是贝壳和被人类食用过的海洋生物骨骼堆成的残骸堆。比如，在东京湾，绳文时代（大约公元前10000年到公元前300年）的贝冢标志着6500-5500年前海水最泛滥时海岸线的位置。当时，经由构造运动，海面与同时期大陆之间的高度差比现在的要多3-5米。对贝壳本身的分析研究也证明了海底地形的变化，因为只有在最高阶段，亚热带软体动物才会出现，这也意味着更高的海水温度。