Author: Pan Yinru
The northern hemisphere has been swept away by a heat wave this summer.
From Europe to China, from India to the United States, and even in the glacier-covered Arctic region, the highest temperature and the number of consecutive hot days have broken records one after another.
On August 9, the World Meteorological Organization (WMO) released the latest report saying that the past July became one of the three warmest July on record.
In the first half of this year, the Intergovernmental Panel on Climate Change (IPCC) successively released the second working group report of the sixth assessment report "Climate Change 2022: Impacts, Adaptation and Vulnerability" and the third working group report "Climate Change 2022: Mitigation". Climate Change, which profoundly reveals the interdependence between climate, ecosystems and biodiversity and human society.
IPCC analysis said that in the past 50 years, global warming has occurred at an unprecedented rate in the past two thousand years, and extreme weather such as heat waves, high temperatures, droughts, and hurricanes will become more common.
"Fire Red Earth"
How hot is the world this summer?
On July 13, the National Space Agency (NASA) released a photo of a "fiery red Earth" on social media.
On this day, NASA monitored that there were high temperatures of 40 degrees Celsius and above in many places in Europe, Africa, and Asia. There were even many black areas in the northern hemisphere in the photo, indicating that the local area was in extreme heat.
In the face of a rare high temperature heat wave of 40 degrees Celsius, two days later, on July 15, the British government declared a "national emergency" for the first time due to the climate.
The Met Office also issued the country's first red warning for "extreme heat" in the country's history.
July 19 was the hottest day on record by the Met Office, with a temperature of 40.3 degrees Celsius.
In previous years, European countries benefited from being located in the temperate oceanic climate and the Mediterranean climate zone, and the average temperature in summer was only 21-27 degrees Celsius.
France, Spain, Portugal, Germany and other places in Europe frequently sounded the "abnormally high temperature" alarm.
According to data from the International Arctic Research Center (IARC), on June 20, 2020, the temperature in the Arctic town of Verkhoyansk in northeastern Siberia, Russia reached 38°C, breaking the highest record ever recorded in the Arctic Circle; in July this year , a high temperature of 32°C was measured in the Bannack region of Norway, which is located in the Arctic Circle.
Every September, NASA tracks the smallest extent of Arctic sea ice—the area where satellite sensors show a single pixel is at least 15 percent covered by ice.
NASA's tracking shows that the minimum extent of Arctic sea ice is decreasing at a rate of 13 percent per decade compared to the average extent between 1981 and 2010.
Sea ice extent in 2012 was the lowest in the satellite record at 3.39 million square kilometers.
In 2021, it will be 4.72 million square kilometers.
In Antarctica, the European Centre for Medium-Range Weather Forecasts (ECMWF) and other institutions have monitored that the sea ice extent monitored in July this year was the lowest in 44 years of satellite monitoring records and 7% lower than the average.
'Synchronized heat waves' occur almost every day
According to a comprehensive analysis of data from 1880 to the present by the National Oceanic and Meteorological Administration (NOAA), global surface temperatures have been on a significant upward trajectory since 1980.
The world's hottest year on record was 2016, with an average annual temperature increase of 0.99 degrees Celsius; it was followed by 2020, with a rise of 0.95 degrees Celsius.
Regardless of whether this year's temperature will finally break the record set in 2016, the consensus of the global scientific community is that extreme high temperature weather will not be an accidental event, but may be "standard" in the future global summer, and the frequency and extreme degree of occurrence will be higher.
The report "How this year's heatwave affects the world and how we can prepare for the future" jointly published by the World Economic Forum (WEF) on July 22 proposed to be alert to the occurrence of "synchronized heatwaves".
The so-called synchronous heat wave refers to the simultaneous large-scale heat wave experienced by any two regions in the middle latitudes (the latitude band between 30 degrees and 60 degrees north latitude).
Over the past 40 years, the frequency of "synchronized heatwaves" has increased sixfold, with a 46% increase in coverage and a 17% increase in maximum intensity.
This summer, "synchronized heat waves" are happening almost every day.
As for the reasons for the increased synchronization of heat waves, the above report believes that, on the one hand, it is a statistical necessity, that is, the more heat waves occur, the higher the probability of high temperatures in various places at the same time; Regions are transported north.
A high-velocity stream, or jet stream, is a fast stream of air in the upper atmosphere that usually travels from west to east.
In addition to meteorological analysis, the IPCC pointed out that in the global warming trend, the factors of human activities cannot be ignored.
In the past 170 years of surface temperature changes, if only natural factors, such as sunshine, wildfires, etc., can push up the global warming to a limited extent, and after adding human activities, the warming changes are almost the same as the current observations.
Be wary of synchrony-enhancing consequences
The effects of climate change intensify for every 1 degree Celsius increase in global temperature.
The IPCC believes that it is an established fact that heatwaves are interacting with many other social and environmental challenges.
These challenges include a growing world population, unsustainable consumption, persistent poverty, land degradation, loss of biodiversity from land-use change, marine pollution, overfishing and ecological destruction, and global epidemics.
The United Nations' "Drought Figures Report" released in May showed that since 2000, the number and duration of global droughts, the most direct "by-product" of heatwaves, has increased by 29%.
Between 1998 and 2017 alone, global economic losses from droughts amounted to $124 billion.
Between 2000 and 2019, drought affected about 1.4 billion people.
The latest report released by the Joint Research Center of the European Commission on August 22 shows that nearly two-thirds of Europe has experienced drought or is at risk of drought this summer, and the drought in some areas has continued to worsen since August, which has affected inland shipping, hydropower and agricultural harvest.
The drought is likely to reduce the production of many crops in Europe this year, resulting in a 16% drop in European corn production this year from the previous five-year average and a 15% drop in soybean production.
This is not good news for the current global food crisis.
Will global warming be "reinstated" in the future?
IPCC believes that this depends not only on future emission scenarios, but also on how humans choose the future economic and social development path.
The IPCC calls on countries to take immediate action to actively fulfill previous climate commitments.
In the above-mentioned series of reports, the IPCC has preset a number of scenarios to study and judge the future warming situation.
For example, if there is no significant reduction in carbon dioxide and other greenhouse gases on a global scale in the next few decades, global warming will exceed 1.5 and 2 degrees Celsius within this century; under the lower emission scenario, global carbon dioxide emissions will be in 2070, respectively. By the middle of this century (2041-2060), global warming will not exceed 2 degrees Celsius, but there is at least a 50% chance that it will exceed 1.5 degrees Celsius in the next 20 years; under the lowest emission scenario, global carbon dioxide emissions will reach net zero around 2050.