冰冻圈

气候变化在冰冻圈中发生的速度和剧烈程度比地球上任何其他地方都要快。

气候变化在冰冻圈中发生的速度和剧烈程度比地球上任何其他地方都要快。“冰冻圈”这个词来自古希腊语中的krúos,意为“非常冷,冰冻”,以及sphaîra,意为“球体”。冰冻圈是指地球上被冰雪覆盖的区域,这些区域可能是季节性的或全年性的。冰盖、海冰、冰川和积雪以及永久冻土在冰冻圈中发挥着重要作用。这些区域共同覆盖了地球表面超过15%的面积。它们是气候变化的明显指示器,这些区域的冰损失增加了全球范围内生态系统和人类社区的风险。早在20世纪90年代,科学家们就已经非常清楚地认识到,二氧化碳排放导致的气温上升正在引起冰冻圈(特别是山地冰川和北极海冰)显著缩小。

几十年的研究成果传递了一个明确而重要的信息:冰冻圈不再只是“煤矿中的金丝雀”或气候变化的早期指示器。随着冰冻圈在全球范围内的退化,其影响已经扩展到远离冰冻圈的地区。融化的冰川和冰盖导致海平面上升;解冻的永久冻土已经向大气中排放了相当于一个大国规模的碳排放;极地海洋酸化从空气中吸收碳并溶解海洋生物的壳体;消失的北极海冰加剧了全球变暖,并加强了欧亚大陆和北美洲的极端天气事件;消失的山地冰川和积雪减少了农业、发电和旅游业的水资源供应。以下的事实表提供了有关这些冰冻圈动态的更多详细信息。

每一分一毫的温度上升都至关重要。

随着每一分一毫的温度上升,由于地球自然冰区的消失所带来的影响将变得越来越灾难性,尤其是当我们超过 巴黎协定 的1.5°C限制,甚至超过2°C时,这种影响将更加显著。

Nearly all of the changes caused by cryosphere loss are essentially permanent, lasting many centuries or thousands of years. The level of damage is going to be set by peak temperature: even a later return to lower temperatures (unless we induce an Ice Age) will not bring most of this ice back. Cryosphere scientists are largely in agreement that even 2°C is too high – we can see in Earth’s past a planet with sea levels 15-25 meters higher than today at that temperature. Physical observations, paleo-record reconstructions, modeling projections and beyond confirm that even 1.5°C is too costly over long periods of time. Instead, we need to see 1.5°C as a guardrail, a level which we should not exceed or exceed only briefly, and even then work to come down below 1°C as soon as possible.

A message of urgency and hope.

The cryosphere is on an accelerated warming path, and some of those changes may drive global climate change faster and further than we are currently prepared to handle. If warming continues unabated, the risks from continuing sea-level rise, flooding, and water resource disruption rise dramatically. So too will the risk of large CO<sub>2</sub> and methane releases from permafrost, potentially eclipsing global efforts to reduce carbon pollution. The window to slow some of these processes may be closing rapidly.

These simple geophysical realities are entirely driven by the melting point of water. By lowering our CO2 emissions primarily from our use of fossil fuels, we can still act in time to curb global temperature rise and limit the loss of these vulnerable snow and ice regions, thereby protecting global health and well-being for generations.

For greater detail, see the State of the Cryosphere 2022 report, written and reviewed by more than 60 leading cryosphere scientists and IPCC authors, released at COP27 in Sharm El Sheikh, Egypt; and the Thresholds and Closing Windows Report, released in conjunction with the 2016 Paris Agreement.

Cryosphere Fact Sheets: English (Swedish versions below)

Click the images below for key facts on some of the most important components of the cryosphere:

Antarctic Ice Sheet

Greenland Ice Sheet

Arctic Sea Ice

Mountain Glaciers and Snow

Permafrost

Polar Oceans

Cryosphere and the 1.5°C limit

Cryosphere Fact Sheets: på svenska

Få viktiga fakta om några av de viktigaste komponenterna i kryosfären genom att klicka på bilderna nedan:

Den Antarktiska inlandsisen

Grönlandsisen

Arktis Havsis

Glaciärer

Permafrost

Polära Haven

Vägar till 1.5°C