Question

Help with reading these graphs. I have a question in my astronomy book with the following graphs and questions, but for the life of me I cannot figure out how to read the graphs. Any help would be appreciated.

A. Examine all of the reconstructed temperatures for the Northern Hemisphere (top graph). Are there other periods that appear to be as warm as the period of 1950 to 2000? If so, list these periods noting how similar they are. (Note that instead of looking at a single study, which could be an outlier, try to focus on groups of studies that show similar patterns. Using a straight edge might help to determine the approximate date(s).)

B. Looking at all data in the 2000 years, approximately how much warmer (e.g. 0.5° C, 1° C, etc.) was the warmest 50 year period than the coldest 50 year period? When was that high and low?

C. What possible major factor do you think could have caused the differences between the warmest and coldest of those 50 year periods?

Thank you in advance!!

Answer 1

A)

1. At around 580-600 years of period, the temperature was a little lower (0.2 ^oC lower) than that of 1950 to 2000 years.
2. Around 950- 1000 years of period, the temperature was almost the same as 1950 to 2000 years.
3. At around 1380-1430 years of period, the temperature was a little lower (0.3 ^oC lower) than that of 1950 to 2000 years.

B)

1.1^oC was warmer than the coldest 50 year period.

In 1950-2000 years, the temperature was warmest (i.e. 0.6^oC).

Whereas in 1430-1480 years, the temperature was coldest (i.e. -0.5^oC).

C) The Warmest years were probably due to the increasing industrial revolution period, where Carbon dioxide emission was high due to which global warming occurred and is still occurring. Whereas the coldest period was due to the excess forests and may be due to high ice deposition at the Earth's surface and very low anthropogenic activity.

These are the main causes due to which this vast difference in temperature was observed on the Earth.