Rising heat on climate change: Tougher the target, greater the cost

The United Nations’ Inter-governmental Panel on Climate Change (IPCC), a collective of more than 2,000 scientists working together, is set to produce a report answering two big questions. One, what would be the impact if global average temperatures rise by 1.5 degree Celsius above pre-industrial era levels? Two, what will it take to keep the temperature rise below this level?

A copy of the draft of the report has already leaked before the IPCC deliberates the final version. Business Standard reviewed a copy of the latest draft, which has been sent to all governments for their comments. 

Under the Paris Agreement all countries agreed to keep global average temperature rise below 2 degree Celsius and to try restrict it further below 1.5 degree Celsius. In this context, the countries tasked the IPCC to write this new report.

The report is likely to become the fulcrum upon which some countries demand, in the next UN Conference of all countries in November, to ramp up existing targets of greenhouse gas emission reductions and financial commitments to help the poor countries do more under the Paris Agreement. 

The draft report reads, “All 1.5 degree C-consistent pathways imply rapid reductions in net global anthropogenic CO2 emissions to reach net -zero around mid -century, together with rapid reductions in other anthropogenic emissions, particularly methane. Greater emissions reductions by 2030 lead to a higher chance of limiting global warming to 1.5 degree C without, or with only limited overshoot (zero 20 to 0.2 degree C)”

In simple words, the scientific panel is of the view that countries would have to undertake much deeper emission reduction targets than the existing ones to keep the global temperatures within the 1.5 degree threshold. The chances of keeping the temperature rise under check would be much higher if the emission reduction targets are enhanced immediately rather than after 2030 (when the first phase of commitments under the Paris Agreement end).

In what is going to put focus on the luxury emissions of rich countries in the global North, the scientists have noted that there are different routes to reach the same destination – keeping the temperature rise below 1.5 degree Celsius. They have said, “1.5 degree C-consistent pathways can have different levels of carbon dioxide removal (CDR). Some limit global warming to 1.5 degree C without relying on bioenergy with carbon capture and storage 4. Behaviour change, demand-side measures and emission reductions in the short term can limit the dependence on CDR” (emphasis added).

In the global climate negotiations, the demand for behaviour change by countries asks nations with high existing levels of per capita energy consumption to reduce their energy footprints and not just ask developing countries to fuel their future growth by cleaner energy sources. This puts additional focus on countries such as the US, which uses much more energy per capita of national income than other developed countries in the European Union. 

The report adds that, “Limiting global warming to 1.5 degree C would require rapid and far-reaching systems transitions occurring during the coming one to two decades, in energy, land, urban, and industrial systems. But it notes the “changes (required) are more rapid and pronounced over the next decades and that there is no documented historic precedent for countries having ever made such scale of changes against such tight timelines.” 

The cost of changing the economy to keep the temperature rise below 1.5 degree C instead of below 2 degree C would be three or four times higher, the scientists conclude. This implies a large economic burden if the countries were to deepen their emission reduction targets under the Paris Agreement. The panel has concluded that this change would require much greater levels of finance and technology being mobilised to support poor countries in this change. 

Consequences of not acting

Why should countries aim to keep the temperature rise below 1.5 degree C instead of the 2 degree C? The scientific panel concludes that there are substantial advantages to be gained from doing so. The impact on climate – extreme weather events, the environment and biodiversity -- gets modulated from medium to high range by keeping the temperature rise at the lower limit. 

The IPCC scientists say, “Limiting global warming to 1.5 degree C, compared to 2 degree C reduces the likelihood of increases in heavy precipitation events in several northern hemisphere high latitude and high elevation regions. Less land would be affected by flood hazards and the probability of extreme droughts would be less in some regions, including the Mediterranean and southern Africa.”

On the impacts on ecology the scientists scanning through the latest science conclude, “The number of species projected to lose over half of their climatically-determined geographic range at 2 degree C is reduced by a factor of two or more at 1.5 degree C. 

They were referring to the fact that changes in climate owing to global warming have reduced the geographical and ecological spaces that each species can inhabit and consequently made them more vulnerable to extinction. 

But this draft report is yet to be deliberated upon by scientists and representatives of all governments. Once they do and come to consensus about the conclusions, the report will be put out in the public domain on October 7. 

Containing climate change: Why countries should aim to keep the temperature rise below 1.5°C 

  • Limiting global warming to 1.5°C, compared to 2°C, reduces the likelihood of increases in heavy precipitation in the northern hemisphere
  • Less land would be affected by floods 
  • The probability of extreme droughts would be less in some regions, including the Mediterranean and southern Africa
  • The number of species projected to lose their natural geographical habitat would be reduced by a factor of two or more


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