“The data showing the patterns of change are strongest in North America, Asia and Europe—mainly because far more studies have been done there, said Rosenzweig. On the other continents, including South America, Australia and Africa, documentation of changes in physical and biological systems is sparse, even though there is good evidence there of human-influenced warming itself.”
The real reason for this is there is no indication of increased temps in the southern hemisphere. The temps in the north seemed to have been rising between 1991-2000. This just happens to correspond to the timing when 100s of measuring stations were shut down in Siberia and northern Russia with the fall of the USSR. The fact of the matter is, neither hemisphere is warming. Don’t let people fool you into accepting there is even such a thing as “global warming” at this time. Does the globe warm...? Of course it does. Does it cool? Of course it does.
Is man the cause of any of this? It has not been proven.
No, the main reason is that the NH is 30% ocean, 70% land, and the SH is 70% ocean and 30% land, and the oceans are warming considerably more slowly than land surfaces. And recently there has been an oceanic shift favoring slightly cooler surface ocean conditions in some regions.