The global climate trend since Nov. 16, 1978 is +0.14 C per decade, according to scientists from the Earth System Science Center (ESSC) at The University of Alabama in Huntsville

April temperatures (preliminary)

Global composite temp.: +0.50 C (about 0.9 degrees Fahrenheit) above 20-year average for April.

Northern Hemisphere: +0.80 C (about 1.44 degrees Fahrenheit) above 20-year average for April.

Southern Hemisphere: +0.21 C (about 0.38 degrees Fahrenheit) above 20-year average for April.

Tropics: +0.63 C (about 1.34 degrees Fahrenheit) above 20-year average for April.

March temperatures (revised):

Global Composite: +0.66 C above 20-year average

Northern Hemisphere: +0.85 C above 20-year average

Southern Hemisphere: +0.46 C above 20-year average

Tropics: +73 C above 20-year average

(All temperature anomalies are based on a 20-year average (1979-1998) for the month reported.)

The most recent El Nino Pacific Ocean warming event might be fading but temperatures in the Arctic hit record highs in April.

April's record high (averaging +2.46 C, about +4.43 degrees Fahrenheit, warmer than seasonal norms) caps the Arctic's warmest five-month period in the satellite temperature record. From December 2009 through April, temperatures in the Arctic averaged 2.07 C warmer than seasonal norms.

November 2005 through March 2006 was the second warmest such period, with average temperatures that were 1.73 C warmer than seasonal norms.

Warmer than normal temperatures have become the norm in the Arctic: There have been only three months in the past decade when average temperatures were cooler than seasonal norms from latitude 60 N (about even with Helsinki and the southern tip of Greenland) to the North Pole.

Globally, April 2010 was the second warmest April in the 32-year satellite temperature record, behind only April 1998 (+0.76 C). The first four months of 2010 were the second warmest start of a year, also trailing 1998.