Increases in atmospheric C02 concentrations driven by human activities alter terrestrial and marine ecosystems and impact on human health, food security and migration trends.
In its latest “State of the Global Climate” report, the World Meteorological Organization (WMO) holds that the 2010-2019 period closes a decade in which the planet's atmospheric temperature acquired exceptional levels, which increased the melting of glaciers and raised the level of seas.
These global transformations are the consequence of the increase in carbon dioxide concentrations in the atmosphere, which exceeded 407.8 parts per million in 2019, a year in which the global average temperature was about 1.1 degrees Celsius above the preindustrial period (1850-1900).
Over the last year, in turn, most of the terrestrial areas of South America, Europe, Africa, Asia, and Oceania experienced unusually hot seasons. In contrast, a large area of North America has been colder than the recent average.
“If we do not take urgent climate action now, then we are heading for a temperature increase of more than 3 degrees Celsius by the end of the century, with ever more harmful impacts on human wellbeing," WMO Secretary-General Petteri Taalas said.
My most popular tweet of 2019:— Gerald Kutney (@GeraldKutney) December 31, 2019
"Every disaster movie starts with the government ignoring a scientist." With climate change, the government is ignoring thousands of them, and this time it is not a movie! - #climatechange #climatecrisis #climatebrawl #climatepoli pic.twitter.com/a9rAckUH8r
“One of the main impacts of climate change is more erratic rainfall patterns. This poses a threat to crop yields and, combined with population increase, will mean considerable food security challenges for vulnerable countries in the future,” he added
In October 2019, due to the melting of ice sheets in Greenland and Antarctica, the global average sea level reached its highest value since January 1993.
This happened because the oceans absorb more than 90 percent of the global climate system's accumulated surplus energy. In 2019, on average, the oceans have experienced about 1.5 months of unusually warm temperatures.
This increase in CO2 concentration also affects the chemistry of ocean ecosystems, generating an increase in the acidity of their waters.
In turn, over the last year, the continued long-term decline in Arctic sea ice was confirmed. Between September 2018 and August 2019, 39 gigatonnes of the ice sheet melted in Greenland.
Changes in global temperature generate events such as floods and droughts, which have a direct impact on human societies.
In the U.S., for example, the precipitation reached 962 mm, which is the highest recorded in the period from July 2018 to June 2019.
In other parts of the world such as Argentina and Uruguay, there were large floods that generated economic losses estimated at US$2.5 billion.
While this was happening in South America, the drought affected many parts of Southeast Asia, Southwest Pacific, and Africa.
I wish everyone in Australia a safe New Year. I wish I could say happy, but there is nothing to be happy about at all when our beautiful country is being decimated by these climate change driven bushfires. Real CC action is required. The clock is ticking, but not for midnight. pic.twitter.com/QtnsvFRji4— ����Michael Springer (@MichaelSpring17) December 31, 2019
Since mid-2019, the countries of the Mekong Basin, Indonesia, and neighboring nations have been suffering exceptionally severe droughts.
Between January and October 2019, Australia experienced the driest season recorded since 1902. Dry conditions also affected Honduras, Guatemala, Nicaragua, El Salvador, and Chile.
The drought is accompanied by "Heat Waves", which happened very noticeably in Europe between June and July.
In the Netherlands, 2,964 deaths were associated with the presence of these heatwaves, which represented almost 400 more deaths than the usual average.
The most dramatic expressions of the combined effect of drought and heat occurred in Brazil and Bolivia, where forest fires were news in the media for weeks.
In these areas of South America, the average number of wildfires increased over the last year.
In 2019, the number of tropical cyclones increased concerning the 1956 average values. While the northern hemisphere had 66 tropical cyclones, the southern hemisphere experienced 27 similar events. Their destructive capacity was also noticeable.
For example, tropical cyclone Idai, which made landfall in Mozambique on March 15, contributed to the destruction of about 780,000 ha of crops in Malawi, Mozambique, and Zimbabwe.
This cyclone displaced 50 905 people in Zimbabwe, 53,237 in Malawi and 77,019 in Mozambique.
Another extreme event was Dorian, a powerful but "slow" hurricane that made landfall in the Bahamas and remained on the islands for approximately 24 hours, which increased the destruction it left behind.
One Of The #ClimateChange Pictures Of The Decade— Allan Margolin (@AllanMargolin) December 31, 2019
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Since 1950, the increase in global temperature has allowed Aedes mosquito species to live at higher-altitude ecosystems, which in turn contributes to the dengue virus spread more easily.
Currently almost half of the world's population is at risk of becoming infected with that disease.
Food security is also negatively affected by changes in the rainy and drought seasons. In southern Africa, for example, the onset of seasonal rains was delayed and there were long periods of drought. As a result, some 12.5 million people will experience severe food insecurity until March 2020.
In contrast, in Afghanistan, food insecurity generated by excess rainfall will affect 13.5 million people. Just a year earlier, however, those same people suffered from hunger due to severe drought.
Natural risks and disasters force people to leave their homes and move to other regions or countries with more favorable living conditions.
In just the first six months of 2019, more than 10 million new internal displacements occurred due to disasters such as Cyclone Idai in Southeast Africa, Cyclone Fani in South Asia, Hurricane Dorian in the Caribbean, and flooding in Iran, Philippines, and Ethiopia.
At the end of the year 2019, however, it is estimated that extreme weather conditions would have forced 22 million people to migrate.