What has the study of marine sediments shown about the Earth's past climate?
I have found why they study them but not what they have shown about the Earth's climate.
- NW JackLv 610 years agoFavourite answer
Oxygen isotope ratios are a proxy for temperature measurements. Annual sediment layers can be countred like tree rings to get the date of when a section was laid down. Grain size depicts flow rates of streams. Large grains mean rushing water forcing large sediment to stay in suspension. Thus, large grain sediments are considered to indicate a period of intense storms, and the absence of large grains in the sediment indicates a calm period.
Using such sediments, support can be found for previous warm periods such as the Medieval Warm Period (MWP), and the Roman Warm Period (RWP). Periods of frequent intense storms are generally associated with cold periods.
In most places, it is possible to find points in the MWP that are warmer than today, but they tend to differ by about a century. Due to the lack of resolution that we have today in the annual, let alone daily temperatures from such proxies, as well as the influence of salinity on the results, peaks in the past record would be smoothed out, and thus, would not peak as if they had been measured with satellites or thermometers as things are done today. It is unknown what the global temperatures would average out to. Thus, there is still a lot of question about just how warm the MWP really was. However, it seems that there was one, and that today's global temperature fluctuations are neither unprecedented, nor abnormal.
Together, they indicate a 1500 year global cycle in temperature based climate change.
- Northern Europe (Shows intense storms associated with colder eras): http://www.sciencedirect.com/science?_ob=ArticleUR...
- North Atlantic Samples from 56 N 14 W, show that the MWP peaked in 750 and 1160 at 2.3 kelvins warmer than today. http://www.falw.vu/~peef/publications_abstracts/pu...
- Bermuda samples show that the MWP peaked about 980, and was about 1 kelvin warmer than 1995 at that location. http://www.nipccreport.org/articles/2010/dec/14dec...
It is about a third kelvin warmer now than it was in 1996. http://www.remss.com/msu/msu_data_description.html...
- Makassar Strait (MWP about 0.4 Kelvins warmer than now)
- Gulf of Mexico (about 1.5 Kelvins warmer than now)
- Puerto Rico: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/nyberg2002/nyberg2002.txtSource(s): Gulf of California: - Article: http://www.sciencedirect.com/science?_ob=ArticleUR... - Graph: http://co2science.org/data/mwp/studies/l2_pescader... North Sea: http://www.sciencedirect.com/science?_ob=ArticleUR... Arctic Ocean: http://www.springerlink.com/content/k3t00102067077...
- andyLv 710 years ago
I know that in Northern Europe and in China they have found plant life in bogs that currently grows up to 300 miles south of where it was found. Anthropologists also have found evidence showing both a warmer climate then now and a cooler climate that stretches from the coast of Western Europe to the shores of China. It also stretches into Africa yet the climate scientists say this is regional only and doesn't count. We still haven't done enough research into the new World to know if these same patterns happened over here.