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    Explained: UN Panel’s five possible temperature rise scenarios

    Explained: UN Panel’s five possible temperature rise scenarios

    Explained: UN Panel’s five possible temperature rise scenarios
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    By CNBCTV18.com  IST (Published)


    'Blah, blah, blah,' environment activist Greta Thunberg had thundered at all the empty talk about climate action that world leaders periodically indulge it. That was a few days back. Now the UN has drawn up five possible scenarios based on the quality of action taken/not taken. Which scenario finally unfolds depends on the leaders and everyone else waking up and collectively walking the talk.

    Climate change is the biggest threat that contemporary humans have to contend with, and possibly the biggest threat they might face for centuries. Rapidly increasing levels of carbon emissions into the atmosphere through industrial and economic activity have led to a gradually accelerating rise in temperature. The temperatures across the world are already higher by 1.2  degrees Celsius when compared to average temperatures in the 1850s-1900s.
    The rapid rise of temperature may seem minuscule but on the planetary level, even such a small increase has already started to show its effects. Climate change is causing natural disasters like record-high heatwaves that turn to deadly wildfires, more frequent erratic weather events like cloudbursts, more frequent and intense climate disasters like cyclones and floods and even lightning strikes.
    The knockdown effect of all the rapid changes in the environment is also leading to the collapse of the global ecosystem. Climate change can lead to faltering crop patterns, death of aquatic life on a massive scale, increased transmission of virulent pathogenic diseases like dengue and potentially other coronaviruses, declining birth rates, adverse mental health due to worries about the future of the planet in the youth, the death of millions of people, and a possible complete collapse of the weather systems that keep our world regulated.
    Faced with such dire threats, governments across the world have pledged in some manner or the other to commit to the goal of keeping temperature rise below 1.5 degrees Celsius, compared to pre-industrial levels. The goals were committed to and enshrined in the Paris Climate Accords, where countries pledged to reduce their net carbon emissions to reach net zero in a timely manner and prevent widespread catastrophe.
    But as the United Nations’ Intergovernmental Panel on Climate Change (IPCC) noted, many nations are failing to meet even the most basic of their commitments and such a failure may have disastrous results for humanity.
    The expert panel in its latest report highlighted five possible scenarios that await humanity depending on the success in reducing carbon emissions in time. Here are the five scenarios.
    is IPCC’s most optimistic scenario, which many already believe is out of reach. The scenario envisions a world where emissions are cut down to net-zero by 2050 and with developing technologies, greenhouses are slowly taken out of the atmosphere. A possible increase of 1-1.8 degrees Celsius is expected by the start of the next century.
    SSP1-2.6 envisages a similar future, but where nations are just not in time to reach net-zero by 2050. While most of the Shared Socioeconomic Pathways taken by governments are the same, they are just a little too late. In such a scenario, the world would already witness a 1.2-1.8 degrees Celsius increase before 2040 and a 1.3-2.4 degrees Celsius increase by 2100.
    SSP2-4.5 scenario sees a world that continues to emit carbon at the levels as today before they start to fall from 2050. With a failure to reach net-zero emissions by 2100, the world witnesses a shattering 2.1-3.5 degrees Celsius increase by 2100. In such a world, several regions across the world, especially in the tropics, become inhospitable due to the increase in average temperatures. Flood and erratic weather events start to become commonplace.
    For scenario SSP3-7.0, instead of global cooperation to tackle climate change, countries instead focus on securing their own geopolitical situation over key resources like water and arable land. A 2.8-4.6 degrees Celsius increase by 2100 and a 7 percent chance of daily rain events intensifying per degree increase would mean a world that is simultaneously being flooded and dried out. Carbon emissions double compared to today and the Arctic Ocean would be free of ice by 2050.
    SSP5-8.5 is the worst-case scenario imagined by the IPCC. The world ignores the threat of global warming, instead focusing on continued and unsustainable economic growth. Carbon levels in the atmosphere double by the year 2050. Weather events are rendered almost unpredictable with intense climate disasters becoming seasonal. Millions stand to die as crops fail around the world and cities submerge under the rising levels of the sea. The world’s temperature increase by 3.3-5.7 degrees Celsius by the turn of the century.
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