United Nations Environment Program: Global warming may temporarily exceed the 1.5 degrees Celsius threshold

According to the United Nations Environment Program (UNEP), the goal of permanently limiting global warming to 1.5 degrees Celsius above pre-industrial levels will not be achieved without experiencing a temporary "overshoot". The agency warned in a new report that temperatures are likely to exceed the 1.5 degrees Celsius threshold in the next few years.

Therefore, the best response path at present is to adopt the "exceed, peak, and fall" strategy: that is, the temperature first rises to more than 1.5 degrees Celsius, reaches the peak at the lowest possible peak, and then falls back below this level.

UN Secretary-General Guterres said: “We must minimize the magnitude and duration of excess warming – that is, limiting the extent of temperature rise and the time it remains above 1.5 degrees Celsius.” For every small increase in temperature, or every additional year above this threshold, the risks and impacts of climate change will intensify.

Global warming is heading towards 2.6 degrees Celsius

The United Nations Environment Program pointed out that according to current climate action measures, the global temperature is heading towards an increase of about 2.6 degrees Celsius compared with pre-industrial levels. Even under the most optimistic scenario, the temperature rise can only be controlled to a maximum of about 1.8 degrees Celsius initially.

Achieving this will require full implementation of national climate plans, additional net-zero emissions targets and rapid and sustained reductions in greenhouse gas emissions. However, the reality is that global carbon dioxide emissions continue to rise, reaching new highs after the COVID-19 epidemic.

"Now is the time to step up climate action, not to give up," said Inger Andersen, executive director of the United Nations Environment Program, when launching the report in Nairobi, Kenya.

The United Nations Environment Program pointed out that necessary measures include accelerating the elimination of fossil fuels such as coal and oil, while accelerating the promotion and application of renewable energy. In addition, significant reductions in methane emissions and greater protection of land, forests and oceans are also critical.

Remove carbon dioxide from the atmosphere

If temperatures are to be brought back below the 1.5°C threshold in the long term after they have temporarily exceeded the 1.5°C threshold, additional carbon dioxide will have to be removed from the atmosphere and permanently stored.

This can be achieved through measures such as afforestation, ecosystem restoration, increasing soil carbon sequestration or using technological means. However, the United Nations Environment Program points out that the gap between the amount of carbon dioxide removal required in the future and the amount that is actually feasible is growing.

The environmental organization Greenpeace is committed to reducing the total amount of carbon dioxide through natural means. Climate expert Jannes Stoppel calls for greater protection and restoration of forests, peatlands and soils, rather than reliance on technological solutions. "The ocean's ability to absorb carbon dioxide has been significantly reduced by climate warming, so forests and soils are the real hope for dealing with excess carbon dioxide," Stopel explained.

In summary, carbon dioxide removal is no substitute for rapid emissions reductions. Rather, it must be part of a comprehensive approach and managed prudently.

Some climate impacts may be irreversible

United Nations experts point out that even temporarily exceeding the 1.5 degrees Celsius warming threshold involves significant risks. Some changes may be sudden, while others may intensify over time, but not all consequences can be reversed later.

The United Nations Environment Program specifically warned that extreme weather events will become more frequent and severe, ecosystems will face loss, and the risk of flooding in small island countries and low-lying coastal cities will also increase. In addition, severe damage to human health, food security, water systems, infrastructure and economic conditions may also occur.

"This summer's scorching heat, devastating wildfires and deadly floods are a warning of things to come," Guterres said.

Adapting to climate change may take decades

UN Environment is calling not only for tighter limits on global warming, but also for greater efforts to adapt to the climate impacts that are already occurring. This includes, for example, better protecting people from heat waves. Establishing effective adaptation measures can take decades, so it is important to start early.

Shobha Maharaj, an academic at the University of the South Pacific, emphasized: "Adaptation must not give way to mitigation: both must be pursued simultaneously, especially in areas where the risk is highest."

In the 2015 Paris Agreement, the international community reached a consensus and agreed to control global warming to well below 2 degrees Celsius and strive to limit it to 1.5 degrees Celsius.