As evidenced by satellite data, the Earth has experienced a positive energy imbalance since 1950, accumulating more heat than it radiates into space. This additional heat warms the land, melts the ice, increases the air temperature, and accumulates in the ocean.
The 2014 global land-ocean temperature index data produced by NASA’s Goddard Institute for Space Studies shows an average rise of 0.12C per decade from 1950 to 2014. In 2012 Nuccitelli et al combined the ocean heat content measurements (surface and subsurface) with the land, ice and atmospheric measurements, showing a global energy increase of 20×10J since 1960.
There is a myth that global warming stopped in 1998—often called a pause or hiatus—because the surface air temperature rose only 0.05C per decade from 1998 to 2012 while atmospheric CO2 levels continued to rise. This argument is flawed for several reasons.
The myth ignores the surface temperature data before 1998 and after 2012. This is an example of cherry-picking: choosing a subset of data to fit an argument while ignoring the data that contradict it. By taking the fifteen year period starting in 1996, one could claim that global warming has increased since the rise for that period was 0.14C per decade. It is only by considering the entire dataset that we see an accurate picture.
The myth ignores the natural variability in the Earth’s climate due to trade winds, sun intensity, and volcanos and assumes the data measures only AGW (anthropogenic global warming). This is an example of misrepresentation. For example, due to the El Niño Southern Oscillation cycle, 1998 saw a particularly strong El Niño warming while 2012 saw a weak La Niña. This caused a considerable ENSO cooling during that period that partially masked the warming trend from AGW.
The myth jumps to the conclusion that a short-term slowdown in the temperature rise will continue forever. There have been similar short-term pauses throughout the twentieth century, but each was followed by a larger short-term rise that offset it. The long-term record shows a clear warming trend of 0.12C per decade.
Finally, the myth focuses on the surface air temperatures and ignores the increasing ocean heat content, increasing sea level, and decreasing arctic sea ice mass—another example of cherry-picking. For example, the Nuccitelli data shows an energy increase of 6×10J since 1998. Taken together, these demonstrate the simple fact that the Earth is warming overall, matching the satellite data.
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