3 ms·

Ya.. ok. but 1951-1980 isn't the 20'th century. It's 29 years.

sintaxi 7y ago
Any average temperature comparison that excludes the 1930's and the Medieval Warm Period is most likely being deliberately deceptive.
- danso 7y ago
  From the GISS FAQ: https://data.giss.nasa.gov/gistemp/faq/index.html#q202 https://data.giss.nasa.gov/gistemp/faq/index.html#q202 > Q. Why does GISS show no data from before 1880? > A. The analysis is limited to the period since 1880 because of poor spatial coverage of stations and decreasing data quality prior to that time. Meteorological station data provide a useful indication of temperature change in the Northern Hemisphere extratropics for a few decades prior to 1880, and there are a small number of station records that extend back to previous centuries. However, we believe that analyses for these earlier years need to be carried out on a station by station basis with an attempt to discern the method and reliability of measurements at each station, a task beyond the scope of our analysis. Global studies of still earlier times depend upon incorporation of proxy measures of temperature change like tree rings, ice core data, etc.
acqq 7y ago
Here you have the last 100 years, it's not better: https://www.climate.gov/news-features/understanding-climate/climate-change-global-temperature https://www.climate.gov/news-features/understanding-climate/...
tzs 7y ago
You can play with a larger range here: https://earthobservatory.nasa.gov/world-of-change/DecadalTemp https://earthobservatory.nasa.gov/world-of-change/DecadalTem...
danso 7y ago
Sorry, I don't work at NASA nor am I a scientist in this field, but it should be obvious there's more to their data and analysis than just what's found on that URL. If you can click around their page and site, you can find a layperson FAQ where they give a broad explanation of their methodology (if you don't want to click through to the cited research papers). Here's the FAQ question relevant to why the 1951-1980 period is chosen: https://data.giss.nasa.gov/gistemp/faq/index.html#q102 https://data.giss.nasa.gov/gistemp/faq/index.html#q102 > Q. Why does GISS stay with the 1951-1980 base period? > A. The primary focus of the GISS analysis are long-term temperature changes over many decades and centuries, and a fixed base period yields anomalies that are consistent over time.

Any average temperature comparison that excludes the 1930's and the Medieval Warm Period is most likely being deliberately deceptive.

danso 7y ago
From the GISS FAQ: https://data.giss.nasa.gov/gistemp/faq/index.html#q202 https://data.giss.nasa.gov/gistemp/faq/index.html#q202 > Q. Why does GISS show no data from before 1880? > A. The analysis is limited to the period since 1880 because of poor spatial coverage of stations and decreasing data quality prior to that time. Meteorological station data provide a useful indication of temperature change in the Northern Hemisphere extratropics for a few decades prior to 1880, and there are a small number of station records that extend back to previous centuries. However, we believe that analyses for these earlier years need to be carried out on a station by station basis with an attempt to discern the method and reliability of measurements at each station, a task beyond the scope of our analysis. Global studies of still earlier times depend upon incorporation of proxy measures of temperature change like tree rings, ice core data, etc.

acqq 7y ago

Here you have the last 100 years, it's not better: https://www.climate.gov/news-features/understanding-climate/climate-change-global-temperature https://www.climate.gov/news-features/understanding-climate/...

tzs 7y ago

You can play with a larger range here: https://earthobservatory.nasa.gov/world-of-change/DecadalTemp https://earthobservatory.nasa.gov/world-of-change/DecadalTem...

danso 7y ago

Sorry, I don't work at NASA nor am I a scientist in this field, but it should be obvious there's more to their data and analysis than just what's found on that URL. If you can click around their page and site, you can find a layperson FAQ where they give a broad explanation of their methodology (if you don't want to click through to the cited research papers). Here's the FAQ question relevant to why the 1951-1980 period is chosen: https://data.giss.nasa.gov/gistemp/faq/index.html#q102 https://data.giss.nasa.gov/gistemp/faq/index.html#q102 > Q. Why does GISS stay with the 1951-1980 base period? > A. The primary focus of the GISS analysis are long-term temperature changes over many decades and centuries, and a fixed base period yields anomalies that are consistent over time.