IPCC Report Analysis: What it'll take to avert an impending global warming fiasco

We are almost, but not completely, out of time to limit temperature rise to 1.5°C, the report warns.

Editor's note: The following is the third in a three-part series about the significance of the recently published UN IPCC Special report, with a focus on impacts in and around the Indian subcontinent.

Part One discussed why impacts rise disproportionately fast for the 0.5ºC rise detailed in the report. Part Two discussed why impacts rise disproportionately fast for the 0.5ºC rise detailed in the report.

These earlier explorations of the 0.5ºC temperature rise and India's particular vulnerability understandably raises some questions.

The big ones: Is there hope to limit temperature rise? What will it take?

Is it possible to cap temperature rise at 1.5ºC?

Scientifically, yes, according to the IPCC report.

The present global average temperature rise is about 1ºC above the pre-industrial level.

However, the world’s oceans have absorbed a lot of the additional heat trapped by greenhouse gases, whose temperature has not yet responded fully.

This means that an additional temperature rise is already “locked in” – and will manifest in the next few years.

The report makes two important points:

  1. Global temperatures are unlikely to rise by 1.5ºC due only to greenhouse gases emitted until today. This gives reason for hope: if we commit to extremely steep cuts in greenhouse gas emissions, we can stay below the 1.5ºC limit.
  2. On the flip side, at current emission rates, temperatures are rising at about 0.2ºC/decade. If we continue along this path, it is probable that we will lock in a global rise of 1.5ºC by 2030 and hit 5ºC between 2030 and 2050.

What is the scale of action that will be required?

One that is an immense, and an unprecedented global challenge.

The report has studied four detailed strategies for emissions reduction that would give us a fighting chance of stabilizing temperatures around 1.5ºC by 2100.

Even the pathway with most flex requires reaching net zero annual emissions in 2055.

In other words, we have 35 years to reach net zero annual greenhouse emissions from present levels — levels we have reached after 140 years of exponentially increasing emissions since the industrial era began around 1880.

Two strategies for reducing emissions between 2020 to 2040 (blue) / 2055 (grey). Notice the speed of rise of CO2 until today vs how rapidly they are required to fall. Source: IPCC Special Report on 1.5C (Summary for Policymakers)

A comparison of two different strategies to reduce emissions, plotted between 2020 to 2040 (blue)/2055 (grey). Notice the speed of rise of CO2 until today vs how rapidly they are required to fall. Source: IPCC Special Report on 1.5°C (Summary for Policymakers)

Yet, the IPCC’s analysis finds that reductions of this scale are, in fact, technically possible.

Several combinations involving a massive uptick in the use of clean energy and reduction in fossil fuels, shifts towards sustainable consumption patterns, afforestation and (relatively untested) Carbon Capture and Storage (CCS) technology could deliver the required emissions cuts.

Action we can take as individuals

Some of these actions pertain to us, as individuals, making lifestyle changes: reducing our use of ACs, private transport and flights, meat consumption, use of multiple devices, etc.

The imperative of system wide action

However, climate change is a systemic problem intimately related to an economic system that demands infinitely rising exponentially growth for prosperity.

Since our industrial era growth has been closely linked to the use of limited physical resources such as fossil energy, metals, minerals and water, the ultimate solution to climate change can only be delivered by global political consensus and system wide transformations.

As the report eloquently states:

Limiting global warming to 1.5°C … would require rapid and far-reaching transitions in energy, land, urban and infrastructure (…), and industrial systems (…). These systems transitions are unprecedented in terms of scale, but not necessarily in terms of speed, and imply deep emissions reductions in all sectors, a wide portfolio of mitigation options and a significant upscaling of investments in those options.

Some limitations of the report

Climate refugees

There are five chapters in the IPCC report written by scientists and a separate concise summary meant for politicians and policy-makers.

The latter is a consensus document that was arrived at through negotiations among the scientists and diplomats at a meeting in October 2018 in South Korea.

Interestingly, the summary for policymakers drops some important points made in the scientific chapters. For example, Chapter 3 states:

A 1°C increase in temperature... was associated with a 1.9 percent increase in bilateral migration flows from 142 sending countries and 19 receiving countries, and an additional millimeter of precipitation was associated with an increase in migration by 0.5 percent (…).”

For perspective, rainfall in Indian cities ranges from 800 millimeters each year in Delhi and Hyderabad to 2100 millimeters in Mumbai.

Twitterstorms and tipping points

Consider a “Twitterstorm” set off by yet another sordid Trump affair.

If a message is retweeted rapidly by a critical mass of people, it enters Twitter’s “trending” list at which point a far larger group of Twitterati pick it up, abruptly amplifying the reach and impact of the initial message.

Entering the Twitter trending list is a “tipping point” – a critical threshold exceeding which may kick off abrupt runaway amplifying effects.

Many tipping points in the climate system are strongly suspected to exist although it is difficult to quantify the “exact” threshold at which each may be triggered. For instance, frozen soils near the Arctic may rapidly thaw above a certain temperature threshold abruptly releasing a vast amount of CO2 and methane greenhouse gases that would accelerate global warming.

Image courtesy:

Image courtesy: "Save The Twinkie" by Nick Anderson for Houston Chronicle

The fear is that the possibility of hitting some of these tipping points increases substantially with temperature rise.

Many examples of tipping points are discussed at length in Chapter three, yet there is no mention of it in the Summary for Policymakers.

The profit-at-all-costs economic system

Finally, although the report dwells on the issue of equity and reduction in inequality, it does little to analyse the viability of the current resource-intensive consumption-centric neoliberal market economy that maximises profit at all costs.

In summary

Limitations notwithstanding, this is an excellent and extremely important report covering every aspect of the science, the impacts and pathways of mitigation and adaptation to climate change.

Its message is both simple and clear:

  • Even a small additional rise in global temperature leads to disproportionate negative impacts in almost every conceivable dimension measuring human and nature’s health.
  • We are almost, but not completely, out of time to limit temperature rise to 1.5ºC.
  • With firm political will and international cooperation, it is yet technically possible to pull back from the brink.


The report tells us what we need to know and how we must respond.

It is for us to make it happen.


The author is a physicist and climatologist.

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