NSIDC publishes graphs like this, so that climate morons can think they are seeing a long term downwards trend of 2 million km² ice loss, and imagine they are really intelligent.
By starting their graphs in 1979, NSIDC is cleverly hiding the two million km² ice gain which occurred prior to 1979. The graph below is from the 1990 IPCC report, and shows the years NSIDC is hiding.
National Geographic published this map in 1971, showing ice extent at the time.
White below shows 1971 extent. Turquoise shows 1979 extent. The purple line is the 1981-2010 median. As you can see, there was a lot less ice in the early 1970’s than at NSIDC’s cherry picked start date of 1979.
Had NSIDC begun their graph in 1971, it would be clear that Arctic sea ice is cyclical, not the fake linear trend they are scamming people with.
But it is worse than it seems – 1971 ice was 1.5 million km² larger than the year before, and there are satellite images.
TimesMachine: Scientists Ask Why World Climate Is Changing; Major Cooling May Be Ahead; Scientists Ponder Why World’s Climate Is Changing; a Major Cooling Widely Considered to Be Inevitable – NYTimes.com
Ice cover increased by 12% in 1972, and climatologists reported a global 1°C drop in temperature since WWII.
So why does NSIDC ignore years before 1979? Starting their graphs in 1979 is wildly misleading, and blatant scientific malfeasance. There is plenty of imagery available back to the 1960’s which they could use to extend a monthly ice graph, as the IPCC did in 1990.
But it is even worse than that. The Arctic was very warm and lost half its ice volume by 1940, prior to the period of 1940-1970 cooling and ice increase.
NASA (who funds NSIDC) doesn’t want you to know about the warm Arctic in 1940, so they simply made it disappear. NSIDC graphs start in 1979, which was the coldest year on record in Iceland. Cherry-picking doesn’t get any worse than what they did.
NASA has completely erased the global 1°C drop in temperature from WWII to 1974.
So next time someone tells you that NSIDC graphs show a “long term trend” – tell them to come here and get their facts straight. Vikings farmed Greenland in the 12th century, where it is too cold to farm outdoors now. NSIDC is ignoring key data, and NASA is actually altering data.