The strong contrast of cold and heat recorded in February, the new normal of climate change

The winter temperatures of the northern hemisphere and the summer temperatures of the southern hemisphere with very varied climatic patterns, and temperatures below and above the average in some parts of the world, highlight the new “climate norms”, says the World Meteorological Organization.

To such an extent the pattern has changed, that the Organization points out that this variation, together with the progressive emergence of new updated climate recording methods, causes the question of what the average temperature is.

A new report from the Copernicus Climate Change Service, conducted by the European Centre for Medium-Term Weather Forecasts, indicates that this disparity occurred with above-average temperatures in northeastern Canada, Greenland and the Arctic Ocean, while Siberia stands out as the region with the most below-average temperatures.

The February weather record showed this variety across much of the Russian Federation and North America with temperatures well below the average observed between 1991 and 2020, but well above average in parts of the Arctic and in a band that extends eastward from northwest Africa and southern Europe to China.

United States: The coldest winter for more than three decades

The United States, with the exception of Alaska and Hawaii, had its coldest February since 1989. According to preliminary data from the U.S. National Oceanic and Atmospheric Administration, between February 11 and 16, 62 daily records for minimum cold temperatures were broken and between February 15 and 16, 69 daily records of maximum cold temperatures were broken.

On the other hand, the sea ice surface in February 2021 was below average in both polar regions, although not exceptionally. In the Arctic, it was below average throughout northeastern Canada, and showed a variety of states throughout Eurasia.

Cold does not attenuate climate change

The Organization stressed that, although February was a relatively cold month, it did not invalidate the evolution towards long-term warming caused by climate change.

Although cold waves are becoming increasingly rare as a result of climate change and there has been a decline in cold temperature records as a result of global warming, cold records and snow will continue to be part of the usual weather patterns in the northern hemisphere winter.

The Intergovernmental Panel on Climate Change affirmed this trend in its fifth Assessment Report.

“It is virtually certain that warm temperatures will occur more frequently and less frequently extreme cold temperatures in most terrestrial areas on daily and seasonal timescales as global average temperatures rise. Heat waves are very likely to occur more frequently and durably. Occasional winter extremes of cold will continue to occur.

At the same time, research continues on how warming Arctic air masses and declining sea ice are affecting ocean circulation and the jet stream, influencing mid-latitude weather.

Greenhouse gas concentrations continue to rise. The Mauna Loa station in Hawaii, which is used as a reference station, reported that average carbon dioxide concentrations in February were 416.75 parts per million, up from 413.4 parts per million in February 2020.

A new standard for measuring temperatures

According to the Copernicus Climate Change Service, the month of February approached the global average recorded from 1991 to 2020. This service has recently changed its starting point for calculating climate averages, an action that has also been introduced by the National Meteorological and Hydrological Services in Europe and in some other parts of the world.

Man-made global warming and its natural variations from year to year, and decade to decade, make up our climate. Therefore, climatologists use standard periods of comparison, as defined by the World Meteorological Organization, to create “climate norms”, averages that represent what can be considered a typical climate for a given period.

Until the end of 2020, the most current and widely used standard reference period for calculating “climate standards” was the 30-year period between 1981 and 2010. A recent meeting of the Organization’s Services Commission recommended the adoption of a new 30-year reference period at the global level, from 1991 to 2020, and pledged support to Members to help them update their figures.

This change is seen as necessary to support decision-makers in climate-sensitive sectors such as agriculture, health, energy, infrastructure and transport.

However, for the purposes of historical comparison and monitoring of climate change, the Organization maintains its recommendation to maintain the period between 1961 and 1990 for the calculation and monitoring of global climate anomalies relating to a fixed and common reference period.

Source: UN News