What is the 1.5 degrees pathway?

While Covid-19 has dominated the world’s news, other issues continue to pose a threat to our planet. These past few years we saw multiple extreme weather events – heatwaves, droughts, floods, and bushfires in many parts of the world. Not only did these cost billions of dollars,  but they also resulted in the loss of thousands of lives.  Many of the events that caused this damage can be linked back to climate change. This is why we are discussing about the 1.5 degrees pathway today.

The 1.5 degrees pathway was first brought into global attention in the Paris Agreement, which is a legally binding international treaty on climate change. It aims to limit the global temperature increase in this century to well below 2 degree Celsius above pre-industrial levels (years 1850-1900), while pursuing the means to limit the increase to 1.5 degrees Celsius.

With the adoption of the Paris Agreement, many countries, through the United Nations Framework Convention on Climate Change (UNFCCC), invited the Intergovernmental Panel on Climate Change (the IPCC, consisting predominantly of eminent scientists in the field of climatology) to provide a Special Report in 2018 on the impacts of global warming of 1.5°C above pre-industrial levels and the related global greenhouse gas emissions pathways.

Why is 1.5°C significant?

The average global temperature on Earth has already increased by 1.1° C (1.9° F) according to an  ongoing temperature analysis led by scientists at NASA’s Goddard Institute for Space Studies (GISS).

The scary truth is that most of this warming occurred since 1975, at a rate of roughly 0.15 to 0.20°C per decade. In recent years, we have already seen more frequent droughts, floods, and other extreme weather events such as bush fire and hurricanes. In fact, the past eight years were the warmest ever recorded.


Annual Temperature Anomaly

Source: NASA Goddard Institute for Space Studies | Anomalies shown relative to 1951 and 1980.

It is difficult to comprehend how much a 1.5°C temperature increase could do to us. After all, we always see temperatures going up and down by more than 1.5°C in a year. When we talk about 1.5°C of warming, we’re talking about the increase in the Earth’s average temperature across the whole surface of the land and sea. Scientists calculate the average temperature changes in different locations from all over the Earth over the course of a year to a produce a single number and look at how this number changes over time. There may be individual cooler or warmer days, but the overall trend is still going upwards.  The 1.5°C warming won’t be distributed evenly. Some regions may see extreme increases in temperatures much higher than the 1.5°C average.

With climate change, the impact is not experienced to the same degree everywhere. The poorest and most vulnerable communities, especially in low-lying regions and coastal communities, will be affected the most. This is because people who are living in  low-income countries are already struggling to provide for their families. Since their livelihoods depend directly on their catches of fishes, livestock or harvest, the ongoing climate crisis threatens their lives and livelihoods. According to the World Bank this could push an additional 132 million people into poverty over the next ten years. There will be more widespread food insecurity, water supply shortages, loss of livelihoods, destruction of homes and forced migrations. These communities are likely to experience more compounded effects, making their ability to adapt much more difficult.

The Difference in Climate Impacts Between 1.5˚C and 2˚C of Warming

There is a very fine balance of environmental conditions required for all life on Earth to thrive. That includes temperature.  Although significant impacts are already expected to occur at 1.5 °C, the risks associated with warming are substantially higher when the average warming reaches 2 °C.  At 1.5°C, adaptation will be relatively less difficult. Our world will suffer fewer negative impacts of the intensity and frequency of extreme events on the resources, ecosystems, biodiversity, and food security. The IPCC projects that going from 1.5 °C of global warming to 2 °C could mean:

  • The coral reefs that support marine environments around the world could decline as much as 99 percent vs 70 percent at 1.5 °C. This could destroy the fish habitats and communities that rely on reefs for their food and livelihoods.
  • Ice-free summers in the arctic sea will be ten times more likely at 2°C s vs 1.5°C. This would not only be devastating for artic wildlife but would also reduce the amount of light being reflected away from earth causing further warming.
  • About 37% of the world population will be exposed to severe heat at 2°C vs 14% at 1.5°C. This is 6 times higher.
  • Global fishery catches could decline by 3 million tonnes at 2°C warming, which is twice as worse than at 1.5°C.
  • 61 million more people in Earth’s urban areas would be exposed to severe droughts in a 2°C warmer world than at 1.5°C.

    Drastic cut of CO2 emissions is needed

    In the past, more than half of all the CO2 emissions since 1751 were emitted in the last 30 years.  Not only have we not succeeded in reducing emissions following warnings on climate change in the late 1980s, instead the emissions have grown substantially. We have now emitted as much CO2 as we had up to 1990.

    According to the United Nations, in order to limit global warming to 1.5°C, annual emissions need to be halved by 2030 and eventually need to reach net zero by 2055.

    Human activities are currently resulting in about 42 billion tonnes of CO2 emissions annually. To achieve  a net-zero by 2055 from the current emission level , a drastic decline in CO2 emissions is required. 

    Take a look at this animation from Carbon Brief: 


    Call for immediate action

    As you can see the transformation required to meet our goals is drastic, thereby urging us to act immediately. All these facts are not meant to scare us but should be seen as a wake-up call to ensure global leaders are taking ambitious actions every year. Each of us has the power to change the emission path and bring about a systemic change – whether it is by writing letters to your local officials, signing petitions or by supporting companies that use renewables. Every small act matters. For more ways to make a difference you could start with any of these 10 changes for climate change.


    All stock images are sourced from Unsplash and Canva




    Written by Shufen Lee

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