Читать книгу World Climate - Terje Instefjord - Страница 4

The first reference point used is the climate 50 years ago, 1967, when the climatic effects of the man-made increase in atmospheric CO2 content were still insignificant.

As shown in Figure 1 below, (Source: National Snow and Ice Data Center, NSIDC), (Ref 1), the 60's were also the last period of what was previously "normal" ice extent in the Arctic.

As shown in the same figure, today's ice extent, especially the summer extent, is significantly less than 50 years ago.

Figure 1 Ice extent in the Arctic from 1850

As shown in Figure 2 below, the global temperature increase from the 80's coincides with the decline in the summer ice extent.

Figure 2 Global temperature variations from 1880

If all current land based ice, mainly in Antarctica and Greenland should melt, the sea level would rise by 65 - 75 meters, depending on sources. (Ref 2) In this book, an average value of 70 meters is used.