Striking graphics from the latest State of the Climate report show how our Earth is warming
The American Meteorological Society released their latest State of the Climate report today, solidifying 2013 as one of the top ten hottest years on record and highlighting the continued rise in global air and ocean temperatures, rising sea levels, the impact of rising temperatures on sea ice in both the Arctic and Antarctic, and some of the extreme weather events experienced due to these trends.
The graphic above shows Earth's surface temperatures, over both land and ocean around the world, from January to December 2013, as they differed from the average set from 1981-2010. As the plot shows, although parts of North America and western South America tended towards below average temperatures for the year, and central Europe had slightly below average temperatures, nearly every other region of the planet recorded average or above average temperatures in 2013. Australia, in particular, recorded their warmest year since record keeping began there back in 1910, and eastern Europe and western Asia experienced temperatures well above normal. Click here for the AMS discussion.
According to the report, for every year from 1976 up to and including 2013 average global temperatures have been above the long-term average. Temperatures over land have warmed by an average of 0.28 C per decade and over the oceans by 0.11 C per decade during those 37 years.
Even the 30-year averages that have been used for climate comparisons have changed dramatically over the years, as shown in the graph above (which has been edited from the original to add in the 1951-1980 average).
Along with the atmosphere, the oceans are warming as well, as shown in the above graphic, which plots sea surface temperatures against the 30 year average from 1981-2010. Although there are some regions that were cooler than normal, especially along the west coast of South America due to the upwelling from neutral El Nino conditions, much of the ocean surfaces had above normal temperatures for the year.
Surface temperature isn't the only aspect to note about the oceans, though, because heat gets circulated down into the depths. The above plot shows heat content of the water reaching down to 700 metres below the surface, as compared to the 1993-2013 average value Click here for the report's summary on ocean heat.
In September 2013, the ice extent didn't reach as low as it had just a year before, when sea ice extent reached its lowest value on record. Despite being predicted by climate scientists, as those kinds of extremes are rarely repeated from one year to the next (due to natural variability in the weather), it was heralded as 'a recovery' by those attempting to downplay the seriousness of the climate change issue. However, sea ice extent still reached its sixth lowest levels on record, continuing the alarming downward trend in Arctic ice.
Conversely, at the other end of the planet, glaciers in West Antarctica continue to lose ice at record rates, which pours fresh water into the ocean surrounding the continent. This results in more sea ice freezing, which is being spread further out from the continent than usual by stronger winds circulating around the land mass. This is resulting in record sea ice extents in the southern ocean, to the tune of over 5 per cent higher than the 1979-2013 average and an increase of a little over 1 per cent per decade.
However, this minor rise in Antarctic sea ice can not, in any way, compensate for the fact that Arctic sea ice was 18 per cent below average last year, and is losing ice at a rate of 13.7 per cent per decade.
According to the report: "From devastating cyclones to crippling drought, this map highlights the events that climate scientists from around the world have concluded should go down in the record books as the year's most significant." Click on the image for the original, or click here for an interactive version of the map.
Not every instance of extreme weather can be directly attributed to the effects of global warming and climate change, of course, simply because we do not have a second Earth to use as a 'control' for comparison. However, as more weather and climate data are gathered, the severity of these events is showing an increase. For example, although there was roughly average tropical cyclone activity around the world, November's Typhoon Haiyan was the strongest of these storms ever recorded - across every part of the planet - to make landfall. Even Tropical Storm Chantal, although it wasn't an extreme storm with regards to strength, clocked in as the fastest moving storm ever recorded in the tropical Atlantic. It's these highly unusual events, along with the rest, that are raising eyebrows and causing concerns for what kind of weather we will see in the future.
This report, accessible in several formats - from simple highlights to the full text report - on the web, is the latest to point out our dire situation. The latest IPCC reports from the past year, the 2014 National Climate Assessment report released by the U.S. government, the Risky Business report that talked about the economic risks faced in the warming world, and now the latest World Meteorological Organization report that pins $2.4 trillion dollars in damages and nearly 2 million lost lives on worldwide weather from 1970 to 2012.