ପାଲିଓକ୍ରଲାମାଟୋଲୋଜିରେ ([[Paleoclimatology|Paleoclimatology]]) ପୁରାତନ କାଳର ଜଳବାୟୁ ବିଷୟର ଅନୁଶୀଳନ ହୁଏ । ଊନବିଂଶ ଶତାବ୍ଦୀ ପୁର୍ବରୁ ବହୁତ ସ୍ୱଳ୍ପ ସଳଖ ପର୍ଯ୍ୟବେକ୍ଷଣ ମିଳୁଥିଲା, ଅଳ୍ପ ଜଳବାୟୁର ହେଉଥିବାରୁ ପ୍ରୋକ୍ସି ଭାରିଏବଲରେ ନନ-ବାୟୋଟିକ ପ୍ରମାଣ ଯେପରିକି ହ୍ରଦ ଶଯ୍ୟା ଓ ବରଫ କୋରରେ ମିଳୁଥିବା ସେଡିମେଣ୍ଟର ପ୍ରୋକ୍ସି ଭାରିଏବଲରୁ ପାଲିଓକ୍ଲାଇମେଟ ଅନୁମାନ କରାଯାଉଥିଲା ଓ ଡେଣ୍ଡ୍ରୋକ୍ରୋନୋଲୋଜି ତଥା isକୋରାଲରୁ theବାୟୋଟିକ studyପ୍ରମାଣ ofମିଳୁଥିଲା ancientclimates.। Since very few direct observations of climate are available before the 19th century, paleoclimates are inferred from [[Proxy (climate)|proxy variables]] that include non-biotic evidence such as sediments found in [[lake beds]] and [[ice core]]s, and biotic evidence such as [[Dendrochronology|tree rings]] and coral. [[Climate model]]s are mathematical models of past, present and future climates. Climate change may occur over long and short timescales from a variety of factors; recent warming is discussed in [[global warming]]. Global warming results in redistributions. For example, "a 3{{formatnum:}}°C change in mean annual temperature corresponds to a shift in isotherms of approximately 300–400 km in latitude (in the temperate zone) or 500 m in elevation. Therefore, species are expected to move upwards in elevation or towards the poles in latitude in response to shifting climate zones".<ref>{{Cite book|title=Biological consequences of globalwarming: is the signal already|last=Hughes|first=Lesley|publisher=|year=2000|isbn=|location=|pages=56|quote=|via=}}</ref><ref name="TIEE-20000201">{{cite journal |last=Hughes |first=Leslie |title=Biological consequences of global warming: is the signal already apparent? |url=http://www.cell.com/trends/ecology-evolution/abstract/S0169-5347(99)01764-4 |date=1 February 2000 |journal=[[Trends in Ecology and Evolution]] |volume=15 |issue=2 |pages=56–61 |doi=10.1016/S0169-5347(99)01764-4 |accessdate=November 17, 2016 }}</ref>
