The Earth reached record warm temperatures in 2015, and brought both an exceptionally strong El Nino and record high levels of greenhouses gases in the atmosphere.
A group of 450 scientists from 62 countries on Tuesday released the annual "State of the Climate" report in the Bulletin of the American Meteorological Society. The report, led by NOAA National Centers for Environmental Information, confirms that 2015 was the Earth's warmest year on record, and with more record or remarkable rises of sea levels, tropical storm activity, wildfires and ice loss.
Many of these records broke those set only the previous year.
One of the strongest El Nino climate patterns seen since the 1950s certainly played a significant role. But the report notes that most of the phenomena seen are characteristic of a planet that is getting warmer over the long term.
Last year was the first time the global annual average land surface temperatures exceeded mid- to late-19th century averages by more than 1 degree Celsius. These averages are generally used to indicate pre-industrial levels.
Measurements of major greenhouse gases reached record levels. Carbon dioxide levels at Mauna Loa, Hawaii, where the oldest carbon dioxide records have been kept, climbed by a record increase to above 400 parts per million for the first time. Average levels for the entire planet were not far behind at 399.4.
Scientists recorded highs of methane and nitrous oxide as well. About 60 percent of atmospheric methane and nitrous oxide arise from natural sources, but the other 40 percent come from human activity. Both also help force changes to climate, and nitrous is known to deplete stratospheric ozone.
Temperatures across land surfaces have reached records on every inhabited continent, and marks of this record warmth have been seen around the world.
As the report notes, a severe heat wave caused more than 1,300 deaths in Karachi, Pakistan, last summer, and 12 countries, including Russia and China, reported record average temperatures. Some of the most intense wildfires ever seen burned across Indonesia, creating so much smoke that the parts of the region could not be seen from space.
Glaciers continued to recede, and researchers recorded melting across more than half of the Greenland ice sheet — something last seen during a previous record melt in 2012. And sea levels rose to new highs, continuing an annual pattern.
There were also quite a few more storms than average along the equator. There were 101 recorded tropical cyclones in 2015, whereas the annual average from 1981-2010 is a mere 82.
Thirty-six of those reached major hurricane intensity, said Jessica Blunden, a scientist for NOAA's National Centers for Environmental Information, on Tuesday's call. "That is about 70 percent higher than the average of 21," she said."So we not only have more storms, we have more intense storms."
This likely has something to do with the strong El Nino, she added, but, it is "also what we expect to see in a warming world."
This means that as even La Nina takes effect in the latter half of 2016, bringing cooler than average temperatures in parts of the Pacific, it is likely that temperatures will continue their climb, said Thomas Karl, director of NOAA's National Centers for Environmental Information, on a call with reporters on Tuesday.
"EL Nino certainly gave it a boost," Karl said. But he added, the planet is still breaking temperature records this year, even though El Nino has decayed.
"It is very likely this year will be a record," Karl said.
Blunden also said that these indicators are higher than they were for the years of the last comparably strong El Nino in 1997 and 1998.
"Every time we have a strong El Nino, the temperature is higher than the previous one," she said, on Tuesday's call. In addition sea ice levels are lower with every cycle and glaciers are melting faster.
Blunden also said some of the effects, such as droughts and effects on ecosystems can have lasting impacts that can span decades.
There were also some of the starkest contrasts ever seen between wet regions and dry ones. Last year brought record rain, along with catastrophic floods, in some regions, while others experienced their worst droughts ever recorded.