No, GW didnt start 400 years ago

Nå går "spagetti"-grafen til IPPC rundt i amatør-fornekter-ekkokammer bloggene. Startet global oppvarming for 400 år siden?

The IPPC "spaghetti-graph is being recycled in the amateur denier echo chamber bloggs these days. Did GW start 400 years ago?

For everyone who needs the graph explained AND to end all these silly misinterpretations of the graph:

Here is what the IPPC report says about the graph (fig 5.7)

"The median of the NH temperature reconstructions (Figure 5.7) indicates mostly warm conditions from about 950 to about 1250 and colder conditions from about 1450 to about 1850; these time intervals are chosen here to represent the MCA and the LIA, respectively."

THERE IS NO DOUBT, THE WARMING CAUSED BY HUMANS STARTED CA 1850:

The Medieval Warm Period and The Little Ice age was also NOT global, like todays warming is (and which also includes the oceans).

https://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_Chapter05_FINAL.pdf

NOAA:

The similarity of characteristics among the different paleoclimate reconstructions of the last 2,000 years provides confidence in the following important conclusions, as reported in the Intergovernmental Panel on Climate Change Fifth Assessment Report:
Dramatic warming has occurred since the 19th century.

For average annual Northern Hemisphere temperatures, the period 1983–2012 was very likely the warmest 30-year period of the last 800 years and likely the warmest 30-year period of the last 1,400 years.

Warmer than average temperatures are more widespread over the Northern Hemisphere since the mid 20th century than in any previous time.

https://www.ncdc.noaa.gov/global-warming/last-2000-years

https://en.wikipedia.org/wiki/Little_Ice_Age

5 centimeters above the picture of the graph, IPPC clearly says there was "colder conditions from 1450 to about 1850":