Long term Warming Trend Continues as U.S. Sees Much Above Normal Temperatures in June

The National Oceanic and Atmospheric Administration (NOAA) today (8 July 2010) released temperature and precipitation data showing that last month was the 8th warmest June on record for the contiguous U.S., continuing a long term warming trend for the month. See the figure below.

As shown on the map below, the warmth was concentrated in the South and East. Delaware and New Jersey broke their June records, while North Carolina tied the record.

For both the southeast and northeast, the last three months (April-June) have been the warmest on record (see below). According to NOAA, "ten Atlantic Seaboard states (Maine, New Hampshire, Massachusetts, Delaware, Rhode Island, Connecticut [tied], New Jersey, Maryland, Virginia, and North Carolina) had a record-warm second quarter. In all, twenty states had their warmest or second-warmest such period on record. "

One consequence of the heat was near record demand for energy to cool our homes. NOAA has developed a Residential Energy Demand Temperature Index (REDTI) to gauge energy demand needed to maintain comfort levels. The REDTI for June -- 11.9 percent above average -- was the second highest in the 116-year record.

While precipitation was normal or below normal in most of the southern half of the U.S., the northern half generally saw above normal precipitation in June. It was the wettest June on record for the East North Central region (see map below). According to NOAA: "June precipitation was the wettest on record for Michigan. Several other states were also anomalously wet, including: Iowa (2nd wettest), Nebraska and Illinois (3rd wettest), Indiana (4th wettest), Wisconsin (5th wettest), Oregon (6th wettest), and Ohio (10th wettest)."

Regional and statewide average precipitation data mask extreme precipitation events which are becoming more frequent and severe as greenhouse gases accumulate in the atmosphere. For example, the southern region had near normal precipitation for the month; and within the region, Texas and Oklahoma were near normal, and Arkansas saw below normal precipitation. But all three states experienced some extraordinarily heavy, localized rains. Tyler, Texas, for example received 9.66 inches (245.4 mm) of rain between June 7 and June 11.

Nationally, the frequency of such precipitation extremes is reflected in NOAA's Climate Extremes Index. Step 4 of the index, covering Jan-Jun from 1910 through 2010 is shown below and represents "twice the value of the percentage of the United States with a much greater than normal proportion of precipitation derived from extreme (equivalent to the highest tenth percentile) 1-day precipitation events. " There has been a dramatic increase in the index over the last 25 years, with January-June 2010 at the second highest level on record.

June also brought a preview of what may be -- in the words of NOAA forecasters -- a "hyperactive" hurricane season: Hurricane Alex, the first Atlantic June hurricane since 1995. According to NOAA, "Alex had sustained winds of 105 mph, marking the most intense Atlantic hurricane during June since Hurricane Alma in 1966."

How you can help: The Senate is set to debate and vote on a climate & energy bill in the final weeks of July or early August (2010). Call your Senators and ask them to vote YES on a climate & energy bill that limits fossil fuel pollution.

Online WWF Resources Regarding U.S. Climate & Energy Policy