ABSTRACT

This essay addresses climate change and its main causes over the last three decades. Between 1992–2021, global emissions of greenhouse gases (GHGs) have risen continually. Specifically, the major socioeconomic sectors – including (1) energy, (2) industry, (3) land-use/land-use change/agriculture, (4) transportation, (5) building/construction, and (6) waste treatment/disposal – have emitted enormous amounts of GHGs. Between 1992–2019, the combined annual GHG emissions have risen by 53% – from 32.6 to 49.8 Gt CO₂ equivalent (CO₂e). The combined GHG concentration has increased by 33% – from 382 ppm CO₂e in 1992 to 508 ppm CO₂e in 2021. The combined radiative forcing has surged by 45% – from 2.226 W m⁻² in 1992 to 3.222 W m⁻² in 2021. At the current emission rate, the entire GHG credit for limiting global warming to 1.5°C or 2.0°C – according to the Shared Socio-Economic Pathway (SSP) 1–1.9 or SSP1–2.6, respectively – in 2100 compared to preindustrial levels may be fully exploited by~2030. Limiting global warming to 1.5°C or 2.0°C will require total GHG emissions to peak before 2025 at the latest, and be reduced by 43% or 25%, respectively, in 2030 relative to 2019, followed by zero net emissions in the early 2050s or 2070s, respectively.

摘要

这篇文章讨论了过去三十年的气候变化及其主要原因。1992 年至 2021 年间，全球温室气体 (GHG) 排放量持续上升。具体来说，主要的社会经济部门——包括 (1) 能源，(2) 工业，(3) 土地利用/土地利用变化/农业，(4) 交通，(5) 建筑，以及 (6) 废物处理/处置——排放了大量的温室气体。1992 年至 2019 年间，每年的温室气体排放总量增加了 53%——从 32.6 增加到 49.8 Gt CO ₂当量 (CO ₂ e)。综合温室气体浓度增加了 33%——从 1992 年的 382 ppm CO ₂ e 增加到 2021 年的 508 ppm CO ₂ e。综合辐射强迫激增了 45%——从 2.226 W m ⁻²1992 年减少到 2021 年的 3.222 W m ⁻²。按照目前的排放率，根据共享社会经济路径 (SSP) 1–1.9 或 SSP1，将全球变暖限制在 1.5°C 或 2.0°C 的全部温室气体信用–2.6，分别为 – 2100 年与工业化前水平相比，到 2030 年可能会得到充分利用。将全球变暖限制在 1.5°C 或 2.0°C 将要求温室气体总排放最迟在 2025 年之前达到峰值，并在 2030 年相对于 2019 年分别减少 43% 或 25%，随后在早期实现零净排放分别是 2050 年代或 2070 年代。