IPCC calls for immediate action rather than rhetorical references to a “climate crisis”

The IPCC report is an important wake-up call to the world to not get taken in by the claim that net-zero declarations of developed countries represent “ambition” in climate action. The real question for countries is how much they plan to emit cumulatively from now until they reach net-zero and whether this is in keeping with their fair share of the carbon budget.

The RWE Niederaussem lignite-fired power station in Bergheim, Germany, a 2020 picture. According to the IPCC report, from 1850 to 2019, approximately 2,390 gigatonnes of carbon dioxide have been emitted, which are responsible, along with lesser contributions from other greenhouse gases, for an increase in global surface temperature by about 1.07 °C above pre-industrial levels.

The recently released report of the Intergovernmental Panel on Climate Change (IPCC), titled “Climate Change 2021: The Physical Science Basis”, is undoubtedly an important advance in the assessment of the current state of the climate system, of how the world’s climate got to where it is today, how the climate is likely to respond to greenhouse gas (GHG) emissions in the near- and long-term future and what it would take to keep the world within the limits of safety.

The report underlines that the impacts of climate change are unequivocally of human origin. The world has already warmed by about 1.07 °C compared with pre-industrial times. To restrict the temperature rise to below 1.5 or 2 °C, which are the targets of the Paris Agreement, the world has very little carbon space left.

The report uses “multiple lines of evidence” to assess more accurately than in previous reports the effects of all GHGs from pre-industrial times to the present. The potential range of future impacts is assessed for illustrative emissions scenarios, ranging from those with assumptions of rapid and sustained emissions reductions to those under which very little or indeed no emissions reduction takes place over this century.

Observed warming, its sources and implications

The report categorically states that the observed increases in the atmospheric concentration of “well-mixed” greenhouse gases (i.e., carbon dioxide, methane and nitrous oxide) since 1750 have been caused by human activities. This increase in GHG concentrations has warmed the atmosphere, ocean and land, causing widespread and rapid changes in the climate system.

Owing to the increase in warming, extreme events (e.g., heat waves, heavy precipitation, droughts, tropical cyclones) have become more frequent and intense. An important advance in the Sixth Assessment Report is that it is now possible to attribute climate extremes to human influence much more confidently than in earlier assessment reports.

That CO2 is the main determinant of global warming and has so far played a dominant role in the increase in global temperatures is now resoundingly clear. This was evident for many years, despite repeated attempts to divert attention from CO2, which arose mainly from industrial processes and fossil fuel energy use and was so far concentrated in developed countries, with, of course, the notable exception of China. While other GHGs do play a role, meaningful and adequate climate action requires strategies targeted at reducing CO2 emissions.

Mitigating air pollution and carbon emissions reduction

This perspective on the role of different sources of warming comes from the report’s assessment of new evidence on the overall effect of a range of different climate forcers from the pre-industrial period (1850-1900) to the most recent decade (2010-2019). Warming driven predominantly by CO2 emissions, together with methane and nitrous oxide, is actually partially masked by aerosol cooling, the latter mainly from sulphur dioxide and organic carbon. From pre-industrial times (1850-1900) to the most recent decade (2010-2019), aerosol cooling has been almost equivalent to warming from CH4 (methane) and nitrous oxides, all of which are “short-lived climate forcers” (a terminology used to indicate their short-lived presence in the atmosphere unlike CO2).

Significantly, the study of the relative importance of aerosols indicates that while climate change and air pollution may have common elements, separate strategies and interventions are required to tackle them. It has been argued of late that getting rid of coal at the earliest would be an effective way to address both air pollution and climate change. The IPCC report makes it clear that this is an incorrect assumption if the aim is the rapid reduction of air pollution, which is an immediate health hazard. The report notes that strategies aimed primarily at CO2 reduction will not automatically achieve the air quality levels recommended by the World Health Organisation (WHO) in many heavily polluted regions of the world, even in scenarios where CO2 emissions reduce very rapidly. Apart from hopefully restraining the more alarmist statements in the media on getting rid of coal, these results should also dampen ill-informed expectations that the rapid reduction of air pollution and CO2 emissions simultaneously is somehow a cost-saving exercise that will benefit developing countries.

Growing gap between climate science and climate policy

But the true value of the report to the fate of humanity depends very much on the willingness of the global North’s political leadership to read the message as it should be done and not twist it to their own partisan ends.

One may argue that this is not a novel situation and that this has indeed been the true story of the tremendous inaction on climate that has increasingly characterised the approach of the rich nations even as the crisis has steadily intensified. Successive IPCC assessment reports, issued in four volumes every five years, have undoubtedly spurred new global policy initiatives, especially in the pre-eminent multilateral forum for global climate action, the United Nations Framework Convention on Climate Change (UNFCCC). This is a message that is frequently heard in the climate commentariat’s general hype that accompanies every new IPCC report. But a more critical view would also contend that, for the last two decades out of the three since the UNFCCC’s entry into force, these initiatives have increasingly been about forcing the global South into bearing the burden of meeting the global warming challenge. Equally, it has been less and less about concerted and determined action by the global North to meet their responsibilities and commitments, inaction that has sharply reduced the South’s options even for poverty eradication, let alone overall development.

This dismal record clearly began with the publication of the Fourth Assessment Report (AR4) that unambiguously pronounced that global warming was anthropogenic in origin and that this warming was unequivocal, which also heralded a policy shift at the 13th Conference of Parties (COP 13) of the UNFCCC, the annual climate summit held in Bali in 2007. Perversely though, Bali turned its back on the unambiguous statement that developed countries ought to take the lead in mitigating GHG emissions with legally binding commitments, as embodied in the Kyoto Protocol, and heralded the consistent recalcitrance of the developed countries to make such commitments. Led by the United States, they have since evaded truly meaningful action, until they were assured that China, India and indeed all developing countries would make equally onerous mitigation commitments, as against the flexibility provided by the climate convention itself.

The publication of the Fifth Assessment Report (AR5) reinforced the messages of AR4 and provided an extraordinary simple metric, namely global cumulative emissions and their linear relation to global temperature rise, for assessing the boundaries for humanity’s safety. Based on this relation, the AR5 indicated that humanity had to live within a global carbon budget, whose limit, up to uncertainties, was determined by the temperature target. The Paris Agreement, signed at COP 21 in 2015, was profoundly influenced by this particular result, but relentlessly chose to turn its back on this result in essence.

On the one hand, the AR5 paved the way, for the first time, to turn away from diffuse targets of atmospheric GHG concentrations to specific temperature targets. The Paris Agreement thus set two targets—to limit temperature increase from pre-industrial levels to well below 2 °C and further to try and restrict it to 1.5 °C. But the agreement studiously avoided any discussion of limiting global cumulative emissions to a definite global carbon budget, and its obvious corollary, of distributing this global budget among all parties on the basis of equity and the principle of common but differentiated responsibilities. Instead, it allowed all parties, including developed countries, to undertake commitments of their choice, the so-called Nationally Determined Contributions (NDCs). The adequacy of such commitments in relation to the temperature targets was left to their being progressively increased in the future.

However, in a transparent move to allow themselves considerable flexibility in future emissions, developed countries argued instead for voluntary declarations of a peaking year for emissions, along with a global goal of reaching net-zero emissions by the second half of the century. It is an elementary mathematical fact that these two restrictions are insufficient to limit cumulative emissions, and hence both may be met, even while temperatures are set to cross the 1.5 °C or the “well below” 2 °C targets set by the Paris Accord, especially when read with the proposed NDCs, whose inadequacy was apparent even before the accord was signed.

The gap between climate policy and science widened when the IPCC undertook the preparation and publication of a Special Report on Global Warming of 1.5 °C, issued in 2018. While the Special Report undoubtedly made the case, perhaps a little ambiguously, for the desirability of the 1.5 °C target as opposed to 2 °C, the case for its feasibility was hardly as clear.

Apart from generalities about the profound, transformative changes required for the lower target, the Special Report had little to say on the socio-economic and policy constraints to attain this goal. Subsequently, the global North launched a vociferous campaign in support of this goal, diluting the carefully crafted ambiguity of the Paris Agreement, supported by an unwary coalition of small island states and least developed countries that have paid little attention to the rapidly diminishing global carbon budget, which is pushing the target out of reach.

Carbon budgets and the myth of net-zero

The first of the four volumes of IPCC’s AR6 emphatically points attention once again to the linear relationship between cumulative emissions and the rise in global surface temperature. According to the report, from 1850 to 2019, approximately 2,390 gigatonnes (1 gigatonne is the scientific terminology for 1 billion tonnes) of carbon dioxide (GtCO2) have been emitted, which are responsible, along with lesser contributions from other GHGs, for an increase in global surface temperature by about 1.07 °C (likely range of 0.8–1.3 °C) above pre-industrial levels. The report also provides detailed estimates of carbon budgets, with different probabilities for varying temperature targets. For instance, for a 50 per cent probability of limiting temperature rise to below 1.5 °C, the total carbon budget available to the world (from pre-industrial times until net-zero emissions are achieved) is 2,890 gigatonnes of CO2.

Further, taking note of the cumulative emissions to date implies that more than 80 per cent of the carbon budget for the 1.5 °C target is already exhausted and that the world has only 500 GtCO2 of emissions left at its disposal. Global emissions databases tell us that developed countries have been responsible for over 60 per cent of these past emissions, and China for about 13 per cent. India’s contribution to these cumulative emissions to date is only 5 per cent. There is greater head room with a higher temperature target, and for a 50 per cent probability of keeping temperature rise below the 2 °C target, the remaining carbon budget is 1,350 GtCO2.

These estimates in the report provide a much-needed perspective on the pressure for net-zero emissions declarations, typically setting 2050 as the target date, that currently threaten to overwhelm the entire discussion on climate change mitigation. In the narrative assiduously peddled by the global North and their developing country apologists, unwitting or otherwise, the declaration of a net-zero emissions target is portrayed as almost heroic climate action, while any argument questioning such targets is sought to be rendered suspect.

But the reality is starkly different. For a 50 per cent chance of limiting temperature rise to below 1.5 °C, the world will have to begin reducing emissions immediately and reach net-zero emissions by 2039. For a better likelihood, for instance a 67 per cent chance, of limiting temperature rise to below 1.5 °C, the world has to reach net-zero even earlier, by 2035.

While most developed countries are still only discussing about reaching net-zero emissions by 2050, few have actually declared this in a manner that can be verifiable by multilateral agreement. But even those who have are targeting net-zero so far into the future that it ensures that the 1.5 °C target will not be met. Even if one assumes that these countries will begin immediate emissions reductions and at a linear rate to meet their declared net-zero targets, they will still end up emitting at least 270 GtCO2 by 2050. This is more than 50 per cent of the remaining carbon budget for the 1.5 °C target. Thus, the developed world, with only about 18 per cent of the global population, is likely to usurp half the space available for remaining cumulative emissions, while the remaining 82 per cent of the world, having emitted very little in the past, will be left with little in the future to meaningfully satisfy their energy requirements.

The IPCC report is, therefore, an important wake-up call to the world for a very different reason than popular narratives would have us believe. It is a call to not get taken in by the claim that net-zero declarations of developed countries represent “ambition” in climate action. The IPCC report’s message is that the real question for countries is how much they plan to emit cumulatively from now until they reach net-zero and whether this is in keeping with their fair share of the carbon budget. Progress towards achieving meaningful climate action requires that the world start asking the right questions.

Crossing the 1.5 °C threshold in all scenarios

The IPCC report also assesses climate responses to five illustrative emissions scenarios, noting that these scenarios are only illustrative—a result of model simulations and do not represent real emissions trajectories which may be influenced by multiple factors. These five emissions scenarios represent five different levels of radiative warming, from the very low to the very high.

A stark finding of the report is that the 1.5 °C target is likely to be exceeded, at least in the near term, under all five scenarios considered. Even in the lowest emissions scenario, the likely range of temperature increase in the near term (2021-2040) is about 1.5 °C, increasing to about 1.6 °C in the mid term (2041-2060), and only reducing to 1.4 °C in the long term (2081-2100).

A significant assumption of this scenario is that negative emissions, or the drawing out of CO2 from the atmosphere by artificial means, will be possible on a significant scale after 2050. But the large-scale deployment of a range of such CO2 removal technologies, most of which are as yet mere speculation, according to the IPCC report itself, is likely to have a number of negative side-effects.

Despite the vociferous campaign that the world must keep temperature rise limited to 1.5 °C, there is clearly little hope that this expectation can be met. Perhaps, in response to this dismal state of affairs, some scientists have turned to mapping out several possible scenarios of very low likelihood but potentially very high impact events.

These scenarios find some space in the IPCC report, though freezing oneself in the fear of an apocalyptic future seems less than useful when the real issue is the lack of political will for climate action in the present.

In sum, there is no doubt that rapid and sustained reductions in global emissions are needed. It is a fact that rich countries are responsible for a significant proportion of these emissions. Their current and proposed climate action is highly inadequate and will likely result in temperature rise that is higher than the Paris Agreement targets.

Even with disproportionately higher action from developing countries such as India, as is already forthcoming, temperature rise is unlikely to remain below 1.5 °C unless the richest countries and highest emitters do far more than they are currently doing or are committing to do in the future.

Declarations of “climate emergency” or rhetorical references to a “climate crisis” mean nothing unless backed by necessary action. The IPCC’s assessment shows that the world needs rapid reductions in emissions by developed countries accompanied by the phasing out of all fossil fuels use (coal, oil, and natural gas), large-scale investment in technologies and their deployment, and the mobilisation of adequate climate finance to support climate action—both adaptation and mitigation—in developing countries.

Tejal Kanitkar is Associate Professor, National Institute of Advanced Studies, Bengaluru. T. Jayaraman is Senior Fellow, Climate Change, M.S. Swaminathan Research Foundation, Chennai.