This is according to the annual state of the climate report released this week by the US Oceanography and Atmospheric Agency NOAA * A weak La Niña period, unprecedented warming of the Arctic region and the breaking of the 400 parts per million carbon dioxide barrier - among the data that affected last year's climate conditions.
In a global calculation, the year 2012 was among the ten hottest years in history. This is according to the "State of the Climate Report 2012" published this week by the American Meteorological Society (AMS). The peer-reviewed report also includes scientists from the NOAA Climate Data Research Center in Asheville, North Carolina, who served as scientific editors. The report was written by 384 scientists from 52 countries and it provides a detailed update on all indicators related to the global climate, noteworthy climate events and other data measured by environmental monitoring stations and facilities on land, sea, ice and the atmosphere.
"Many of the events that made 2012 an interesting year are part of a worldwide trend that we are seeing in a changing and diverse climate. Carbon levels are on the rise, sea levels are on the rise, the sea ice in the Arctic Ocean is melting, and our entire planet is becoming a warmer place," says NOAA Acting Director, Prof. Kathryn Sullivan.
Conditions in the Arctic Ocean were the big story of 2012, with this region breaking several records. Sea ice shrank to the smallest summer minimum since satellite measurements began 34 years ago. In addition, over 97% of the Greenland ice sheet showed varying degrees of melting during the summer, at a rate four times greater than the average melting in the years 1981-2010.
The report uses dozens of climate indicators to track and identify changes and trends in the global climate system. These indicators include the concentration of greenhouse gases, temperatures of the lower and upper atmosphere, cloud cover, sea surface temperature, sea level rise, ocean salinity, sea ice and snow distribution. Each index includes thousands of measurements from independent databases.
- Trends of warm temperatures near the ground surface: four separate databases showed that 2012 was in the top ten of the hottest years - in some databases it is in eighth place and in others - in ninth place. The hottest temperatures in history were measured in the USA and Argentina.
- La Niña has dissipated to neutral conditions: A weak La Niña dissipated during the spring of 2012, for the first time in several years the climate is not affected by El Niño or La Niña, and in most years, one of these phenomena occurs.
- The Arctic Ocean continues to warm: the sea ice cover reaches a negative peak. The rate of warming in the arctic region is twice the average rate and that which occurs in the low latitudes. The minimum ice cover in September and the Northern Hemisphere ice cover in June reached historic lows. Minmal ice cover (3.4 million square kilometers on September 16) was the lowest in the satellite era. This is a decrease of 18% compared to the previous negative record, 4.17 million square kilometers in 2007 and 54% lower than the ice surface in September 1980. The heat measurements of the permafrost areas on land reached high levels when a new record in permafrost melting was recorded on the 11 -July 12 in Greenland when 97% of the land covered by frost showed the mass to be greater than average.
- Antarctic sea ice reached an all-time high of 19.45 million square kilometers on September 26, an increase of half a percent compared to the previous record in 2006.
- Sea surface temperatures are rising: Four independent databases have shown that the global average of sea surface temperatures is among the 11 warmest years on record. After a period of 30 years - 1970-1999 - of rising temperatures, in 2000-2012 there was a stabilization of the high levels. These differences are related to the prevalence of La Niña-like conditions in the 21st century, which leads to a decrease in surface temperature.
- The temperature of the top kilometer of the sea surface reached record levels in 2012, the overall increase from 2011 to 2012 appeared at depths of over a kilometer.
- Sea level breaks records: following a drop in sea level in the first half of 2011 that is related to the effect of La Niña, the sea level returned and rose and even broke new records in 2012. Currently, the sea level is rising at a rate of 3.2 ± 0.4 mm per year in the last two decades.
- The trend of salting seawater continues. This is a trend that has been going on since 2014 according to which the oceans are becoming saltier than average in areas with high evaporation, such as the central tropical area in the North Pacific Ocean, and milder than average in areas with a lot of precipitation, such as the northern Indian Ocean, which shows that investors are growing in areas that are already rainy and evaporation is increasing in dry areas .
- Tropical cyclone activity was close to average: Tropical cyclone activity during 2012 was close to average. 84 storms occurred there compared to the proposed 89, and similar to 2010 and 2011. The North Atlantic Ocean was the only hurricane area that experienced greater than average activity.
- The level of greenhouse gases climbed: The concentration of the main greenhouse gases, including carbon dioxide, methane and nitrogen oxides, continued to climb in 2012. Despite a decrease in emissions resulting from the economic crisis, emission levels reached 9.7 petagrams of carbon, compared to 9.5 petagrams in 2011. The concentration of carbon dioxide in the atmosphere increased by 2.1 parts per million and reached 392.6 parts per million. In the spring of 2012, for the first time, the carbon dioxide concentration reached 400 parts per million at several measurement sites in the Arctic region.
- Cold temperatures continue to be measured in the lower part of the stratosphere: about 10-15 kilometers above the surface of the earth. In 2012, a measurement of almost a negative record was recorded - according to the data series. The increase in greenhouse gases and the decrease in the ozone level in the stratosphere tend to cool the stratosphere and warm the layers closer to the atmosphere.
