Blue Book on Climate Change of China 2024 unveiled –

Updated: 05-07-2024
Source: China Meteorological News Press
On July 4, Blue Book on Climate Change of China 2024 (hereinafter referred to as the Blue Book) was unveiled, which focused on the latest monitoring information on the state of climate change in China and globally from the perspectiveof atmosphere, hydrosphere, cryosphere, biosphere and climate change drivers.

The Blue Book noted that the global warming trend continued. Analysis of the global surface temperature dataset of China Meteorological Administration (CMA) showed that the global average temperature in 2023 had beenthe highest since meteorological observations were recorded in 1850, and that the global average temperature in the last 10 years (2014-2023) is about 1.2°C higher than thatin pre-industrial level (1850-1900). The regional average temperature in Asia in 2023 is 0.92°C above the normal figure, the second highest since 1901 and the annual average surface temperature in China in 2023 was0.84°C above the normal figure, the warmest year since 1901.

Global mean temperature anomaly from 1850 to 2023 (relative to the average from 1850 to 1900)
Extreme weather and climate events tend to be more frequent and severe. In China, extreme high temperatures and heavy precipitation events tend to be more frequent and severe, while extreme low-temperature events have generally declined. The average number of dust and storm days in the northern region has shown a significant trend of decline, reaching a minimum in recent years and recovering slightly. And the average intensity of typhoons that have made landfall in China has fluctuated and strengthened since the late 1990s.

The frequency of extreme heat duration in China from 1961 to 2023
Warming of the oceans has accelerated significantly, with sea surface temperatureand ocean heat content reaching new highs and the global average sea level continuing to rise.China's coastal sea level wasgenerally on an accelerating upward trend, and in 2023 it wouldbe 72 m higher than the average figurefor the period from 1993 to 2011.

The change of anomalous variation in global ocean heat content (upper 2000 m) from 1958 to 2023

Global glacier retreatwasaccelerating and in a state of high material deficit.The extent of Arctic sea ice wasshowing a significant trend of reduction and the mountain glaciers in West China showedan increasing trend of melting. The degradation of perennial permafrost along the Qinghai-Xizang Highway is obvious.
China's overall vegetation cover has increased steadily, showing a trend of continuous greening.From 2000 to 2023, Chinas average annual  Normalized Difference Vegetation Index (NDVI) has showed a significant upward trend, and in 2023 it reached the third highest figuresince 2000.

Average annual NDVI from Earth Observation System/Moderate-resolution Imaging Spectroradiomete (EOS/MODIS) in China from 2000 to 2023

Focusing on climate change drivers, the Blue Book showed that global concentrations of major greenhouse gases are risingannually.Global average atmospheric concentrations of carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O) have all reachedthehighest levels since observations began.

All data graphs are from National Climate Centre (NCC)

Editor: JIANG Zhiqing