202 1 Four more climate change records were broken.

From 20 15 to 202 1, these seven years are the hottest on record. In 20021year, the global annual average temperature is about1.1℃ higher than the industrial average before 1850-65438.

The World Meteorological Organization (WMO) released the latest report "Global Climate Status", in which four key climate change indicators set a new record in 20021year. They are greenhouse gas concentration, sea level rise, ocean heat and ocean acidification, which reveal the influence of human activities on global climate change. Let's see what these indicators mean.

Greenhouse gases include carbon dioxide, methane, nitrous oxide, natural water vapor and synthetic fluorinated gases. These gases are like blankets covering the earth, firmly covering the heat generated by solar radiation in the earth's atmosphere.

In 2020, the concentration of greenhouse gas carbon dioxide (CO2) will reach 4 13, the content of methane will be 1 billion 1889, and nitrous oxide will be 3,332 billion, setting a new global record. These accounts for 149%, 262% and 123% of the pre-industrial level respectively.

Greenhouse gas is one of the main driving factors of climate change, which not only affects the environment, but also affects human health, agriculture and economy. Methane in the atmosphere is particularly worrying, because it is a harmful pollutant, which causes 654.38+0 million premature deaths every year due to exposure.

"The report emphasizes that by 2022, carbon dioxide in the atmosphere may exceed 420 ppm (one in a million). The ice core records from Antarctica show that the natural fluctuation of CO2 in the atmosphere is between 150 and 300 ppm, which indicates that "we may now be 40% higher than the natural level of CO2 experienced in the past10 million years in the history of the earth, and all this happened in the past 150 years".

There are two different ways for global warming to cause sea level rise. First of all, the rising temperature of air and ocean causes glaciers and ice sheets to melt, thus injecting more water into the ocean. Secondly, with the warming of seawater (see ocean heat below), due to the principle of thermal expansion and cold contraction, hotter seawater occupies a larger volume than cold seawater.

From 1993 to 2002, the global average sea level rose by 2. 1 mm every year. From 20 13 to 202 1 year, this figure increased to 4.5 mm per year, mainly due to the accelerated loss of ice sheets.

These rapidly rising sea levels have led to the disappearance of at least five islands in the Pacific Ocean, which has caused communities to face more big tides, tropical cyclones, droughts and soil salinization, leading to more crop failures and the collapse of marine resources.

According to the report, even in the case of very low emissions, the sea level will rise by 28-55 cm by 2 100, and in the worst case, high emissions will lead to a sea level rise of 63-10/cm. It is hard for us to imagine what kind of damage this will cause.

Most of the excess heat of greenhouse gases (more than 93%) is absorbed by the ocean, which leads to the rise of ocean temperature. The ocean temperature has reached an all-time high. In the past two decades, the speed has been particularly accelerated, and the temperature has penetrated into deeper and deeper marine waters.

Ocean warming may lead to extreme weather events, melting of polar ice shelves, accelerated sea level rise and large-scale destruction of marine ecosystems.

As the oceans get warmer, their heat fills the weather system, leading to more rainfall and more powerful storms. This may lead to extreme floods and snowfall.

Rising ocean temperatures also lead to coral bleaching and the loss of breeding grounds for marine species. Fisheries and aquaculture provide 15% animal protein supply for 4.3 billion people, and the economic losses caused by ocean warming alone may be as high as several billion dollars.

The ocean absorbs about 23% of man-made carbon dioxide emissions every year, which helps to mitigate the impact of climate change, otherwise these carbon dioxide will rise to the atmosphere. However, this reacts with seawater and lowers the pH value of the ocean.

The pH value of the ocean has dropped from 8. 1 1 in the late 1980s to below 8.06.

Ocean acidification particularly affects shellfish species, including oysters and corals that make up Australia's Great Barrier Reef. These creatures combine calcium and carbonate in seawater to make shells and bones.

With the intensification of ocean acidification, the pH value is lower, and there are fewer ions for organisms to build their hard structures. If the pH value is too low, shells and bones may even start to dissolve.