EMERGING EMITTERS AND GLOBAL CARBON MITIGATION EFFORTS

International efforts to avoid dangerous climate change have historically focused on reducing energyrelated CO2 emissions from countries with the largest economies, including the EU and U.S., and/or the largest populations, such as, China and India. However, in recent years, emissions have surged among a different, much less-examined group of countries, raising the issue of how to address a next generation of high-emitting economies that need strong growth to reduce relatively high levels of poverty. They are also among the countries most at risk from the adverse impacts of climate change. Compounding the paucity of analyses of these emerging emitters, the long-term effects of the COVID-19 pandemic on economic activity and energy systems remain unclear. Here, we analyze the trends and drivers of emissions in each of the 59 developing countries whose emissions over 2010-2018 grew faster than the global average (excluding China and India), and then project their emissions under a range of pandemic recovery scenarios. Although future emissions diverge considerably depending on responses to COVID-19 and subsequent recovery pathways, we find that emissions from these countries nonetheless reach a range of 5.1-7.1 Gt CO2 by 2040 in all our scenarios—substantially in excess of emissions from these regions in published scenarios that limit global warming to 2C. Our results highlight the critical importance of ramping up mitigation efforts in countries that to this point have played a limited role in contributing the stock of atmospheric CO2 while also ensuring the sustained economic growth that will be necessary to eliminate extreme poverty and drive the extensive adaptation to climate change that will be required.

C a n C u i D a b o G u a n D a o p i n g W a n g

Introduction
Fossil fuel carbon dioxide (CO2) emissions are the largest contributor to global warming. Going back to the 1990s and before, analyses of fossil emissions and energy-emissions models (IAMs) have focused on a handful of regions that include industrialized economies where emissions have been high (US, EU), and rapidly-industrializing countries such as China and India (Raupach et al. 2007;Fernández González, Landajo, and Presno 2014;Hubacek, Guan, and Barua 2007;Cantore and Padilla 2010). To the extent other countries are included, they are typically heavily aggregated, often literally into a "Rest Of World (ROW)" group, or "other developing countries" in the non-Annex I countries' list of UNFCCC (Winkler, Brouns, and Kartha 2006). Yet, since 2010, most of the growth in global emissions has been among these non-annex I, "ROW" countries. Over 2010-2018, all the countries with an emissions growth rate higher than the world average are developing economies, including countries currently in the lists of the least developed countries (LDCs) and/or landlocked developing countries (LLDCs) (IEA 2018a; United Nations 2020).
In contrast to large emitters, such as the United States, China and India, these developing countries individually have small emissions, but collectively the emissions are comparable with those of the top emitters and have a large potential to dominate global emissions in the future. These countries face multiple daunting challenges. Many of these emerging emitters face high costs in adapting to climate change while having the weakest adaptation capacity. At the same time, they need to sustain economic growth to generate jobs and lift people out of poverty. It is this growth that is accelerating the rise of their global CO2 emissions and leads to the challenge of implementation of their intended nationally determined contributions (INDCs) toward climate change mitigation. A key issue is the increasing demand for oil and rising coal-related CO2 emissions that may cause a lock-in of emission-intensive energy use patterns among Asian (Steckel, Edenhofer, and Jakob 2015) and African countries (IEA 2019a, Steckel et al. 2020, Lucas et al. 2015.
Following the COVID-19 pandemic outbreak, countries have applied various lockdown measures to avoid the rapid spread of the virus. As these lockdown strategies limit production and consumption activity, they are having a significant impact on energy consumption and CO2 emissions (Le Quéré et al. 2020;Liu et al., n.d.). For example, the world's energy demand in the first quarter of 2020 declined by 3.8% relative to Q1 of 2019 (IEA 2020), and global CO2 emissions were over 5% lower in Q1 2020 than in Q1 2019 (IEA 2020). The severity of the pandemic and the strictness of the lockdown measures vary among the emerging emitting developing countries. For example, Peru has experienced severe outbreaks with over 835,000 cases and over 33,000 deaths as of October 2020 (World Health Organization 2020), although with a prolonged lockdown. Vietnam applied strict lockdown measures early in the outbreak and largely succeeded in controlling the spread of COVID, with 1,100 cases by October 2020 (World Health Organization 2020).
Since COVID is projected to re-emerge and have impacts for nearly four years (Kissler et al. 2020), it might reshape the emission pattern of the emerging emitters and substantially influence their future emissions.
Therefore, understanding the driving forces behind previously growing emissions, the impact of COVID and likely future trajectories of CO2 emissions of these developing countries is essential in the context of measures to achieve global emissions reduction. Although, even prior to COVID, emissions of some major economies were declining (US, EU) (Le Quéré et al. 2019) or had at least flattened (Guan et al. 2018), few studies have focused outside of those main regions, on countries where growth rates are high but emissions remain relatively low for now. Here, we comprehensively assess the situation of these emerging emitters, develop country-specific emissions scenarios that capture the impact of COVID and finally discuss potential measures for global emission reduction.
In this study, we use index decomposition to analyze the drivers of emissions of 59 fast growing developing countries. We then develop country-specific emission scenarios for a range of future energy and development trajectories using an Adaptive Regional Input-Output (ARIO) model. These capture regionspecific COVID effects combined with more aggregate shared socioeconomic pathways (SSPs) generated by large Integrated Assessment Models and assumed application of low-carbon technologies in the emerging emitters. Located in Asia, Africa, and Latin America, these 59 developing countries discharged CO2 emissions of between 0.7 Mt (Eritrea) and 542.9 Mt (Indonesia), individually much smaller emissions than the emission giants in North America and Europe. However, the 59 emerging emitters as a group accounted for growth of CO2 emissions from 2.7 Gt in 2010 to 3.8 Gt in 2018. These countries combined now emit 65% more than India, which has the 3 rd largest emissions at 2.3 Gt. Specifically, the 1.1 Gt of increased emissions from these countries contributed to almost 40% of the world emissions growth over this period, signaling a new generation of emerging emitters.

Figure 1 | Map of countries with fast-growing CO2 emissions.
Note: The depth of purple reflects the volume of emissions in 2018, and the size and the color of the bubbles represent the annual growth rate of emissions (2.5% is the global average), green for declining, yellow for slowgrowing, and red for fast-growing.
The average annual emission growth rate of the 59 countries was 6.2%, much higher than the global average of 2.5%. The average annual growth rate of GDP of the 59 countries' GDP was 4.6%. Over half (34 out of 59) of this group of developing countries have experienced emission growth faster than GDP growth over the past decade and 12 have seen emission grow at twice the rate of GDP growth. These countries are in diverse stages of development ranging from LDCs, such as Ethiopia and Uganda, to economies in transition (EIT)(United Nations 2020), including Georgia. For most LDCs and LLDCs the increase in emissions appears to be strongly coupled with GDP growth (mapped as bubbles above the lines of slopes of 1 and 2 in Figure 2, which represent a 1 to 1 and two to one ratio of emissions growth to GDP growth respectively).
These countries include Laos, Zambia, Myanmar, Ethiopia, Georgia, Uganda, and Vietnam. There are another 25 countries for which CO2 emissions have grown more slowly than GDP, including Mongolia, Ghana, and Peru. We now move to discuss how the diverse natural and economic situation of these countries has shaped different patterns and drivers of CO2 emission growth.

Figure 2 | Relative increase of CO2 emissions and GDP in 2018 over 2010
Notes: Each bubble represents a country, plotted by GDP increase in 2018 relative to the level of 2010 on the horizontal and CO2 emissions increase on the vertical. The bubbles of countries with below 100% emission increase (within the black dotted box) in the left part are zoomed in on the right part. The size of the bubbles represents the amount of CO2 emissions in 2018. The colors represent the developing stages of the countries (United Nations 2020), red for developing economies (DE), cyan for economies in transition (EIT), green for least developed countries (LDC), and purple for landlocked developing countries (LLDC). The two grey lines with slopes of 1 (lower) and 2 (upper) mean the CO2 emission growth rate is the same as or twice the rate of the GDP growth. The figure includes 57 countries (South Sudan and Eritrea lack GDP data).

Emerging emitters carbonizing together, but in diverse ways.
To understand the driving forces behind these fast-growing emissions we decompose emissions growth (C) over 2010 to 2018 into contributions from six factors: CP from population (P) growth; CG from economic growth measured by GDP (G) per capita; CIS from industrial structure (IS), as reflected by changes in the share of primary industry, secondary industry, and tertiary industry in GDP; CEI from energy intensity (EI) defined as energy consumption (E) per unit of GDP; CES from energy structure (ES), the share of energy consumption of coal, oil, natural gas, and other energy sources; and CCI from CO2 emissions intensity (CI) which is the emissions per unit of energy consumption, as follows: Where, i refers to the ith industry in primary industry, secondary industry, and tertiary industry; j refers to the jth energy type in coal, oil, natural gas, and other types. The change in C from time 0 to time T can be divided into six parts using the logarithmic mean Divisia index (LMDI) method as follows: Where, Xij refers to the driving factors, i.e. P, G, ISi, EIi, ESij, and CIij. We select Myanmar, Ethiopia, Vietnam, Uganda, Mongolia, and Peru as case countries to reveal the different drivers of emission growth.
The results are shown in Figure 3 and are summarized below for each country: Myanmar ( consumption, and energy intensity as the top three contributors. GDP growth has been the main driving force of emission increments. Next, the energy structure of Myanmar has become oil-oriented, especially in construction, power generation, manufacturing, and household sectors. Further, shifts in the structure of industry towards manufacturing, a key factor behind Myanmar's success in poverty reduction, have also contributed to increasing CO2 emissions.
While economic development has progressed in Myanmar, substantial potential remains for sustained economic growth. On the one hand, this will contribute further to growing CO2 emissions, but on the other hand, it is essential to continue to take people out of poverty, including the more than three-quarters of a million people still in extreme poverty. At the same time, Myanmar is ranked 160 out of 181 countries on the ND-Gain index which measures a country's vulnerability to climate change together with its capacity to improve resilience. Myanmar is also second on the Germanwatch list of countries most impacted by climate change over the past 20 years.

Figure 3 | Drivers of Emissions Growth in Case Study Countries
Notes Carbon emissions also increased slightly more than GDP with an annual average growth rate of 6%, increasing to 5 Mt in 2018. Increasing population and oil consumption were the main impetus behind the growth of emissions in Uganda, contributing 37.0% (1.1Mt) and 27.6% (0.8Mt) to the CO2 emission increment, respectively. Uganda saw a 3.6% annual average population growth rate over 2010-2018, and its net population increase was 10.29 million. Over the period, oil consumption increased at an annual growth rate of 7.1%, which also contributed substantially to the increase of CO2 emissions. The increasing contribution of services to GDP and, in particular transport services, also added to the growth of CO2 emissions. On the other hand, investments in renewable energy led to a lower energy intensity that reduced the growth of emissions by 1 Mt over the period.
Uganda has yet to achieve the sustained inclusive growth necessary to drive poverty reduction. The absolute increase in the Peruvian population, was, in part, due to the young population structure, but was also the result of higher immigration, especially from Venezuela. By 2018, more than three million immigrants have been officially accepted by the Peruvian government. Both industry and changes in CO2 intensity contributed to substantial reductions in emissions over the period, amounting to over 14 Mt, offsetting to a large degree the increases driven by population growth and increases in GDP per capita.

Future emissions: COVID19 delay and potential mitigation
Economic development will continue to be a strong driver of emissions growth in these developing countries and essential to eliminate extreme poverty. Nevertheless, as the experiences of some of the countries discussed above has shown, structural changes in these economies towards less carbon intensive activities, such as, shifting away from coal to other less carbon intensive sources of energy, and improvements in the energy intensity of GDP can significantly dampen the growth in emissions from these emerging emitters. An additional factor impacting the trajectory of emissions from these and all other countries is the COVID-19 pandemic and economic slowdowns resulting from countries applying lockdown strategies to limit the spread of the virus. We now move to model the impact of COVID-19 scenarios on the emissions growth of these developing countries and how this may impact on overall emissions by 2040 and on achieving the objective of limiting global warming to 2C .
We use the projections from GAINS 4 and an ARIO model (see Annex 2 for description of the modelling approach) to explore a scenario for the impact of COVID and then, after 2024, supposing that COVID is To investigate the short-term (next five years) changes in emissions brought about by the sudden shock of COVID-19, we assume that production efficiency and economic structures are unlikely to change significantly within such a short time. The relationship between emissions and GDP (the emission intensity) will not be altered. Therefore, we simply estimate the emissions of countries based on their sectoral emission intensities and economic outputs: . Therefore, we assumed the countries reach the regional average emission intensity (emission per unit GDP); and based on that emission intensity and the country-level GDP forecast, the region-level emissions are allocated to country level. 6 Low-carbon technologies (LCT) applied from 2025 (linearly increasing in application and fully applied by 2040), including carbon capture and storage (CCS), renewable energy for the production of newly-demanded electricity, and electric vehicles replacing the newly-increased oil fueled automobiles from 2030. More specifically, countries are categorized into two groups, thermal-powered countries and non-thermal-powered countries, according to whether the percentage of thermal-powered emissions over total emissions is greater than 50%. For the thermal-powered countries, the low-carbon technology for the power sector is set as CCS and for the non-thermal-powered countries the lowcarbon technology is set as renewable energy for power generation. Both are applied to newly-demanded electricity, linearly increasing in coverage from 0 in 2025 to 100% in 2040.
renewable energy for power generation, and with electric vehicles replacing oil fueled automobiles, and a weak policy scenario (WPS) where no low-carbon technologies are applied (i.e. the SSP2 scenario from the GAINS model, a middle of the road scenario in terms of mitigation and adaptation).
As shown in Figure  If large scale adoption of low-carbon technologies were applied from 2025, including CCS (carbon capture and storage) and renewable energy for power generation and electric vehicles in place of oil-fueled automobiles, the aggregated emissions of these countries could be reduced by 611 Mt CO2, 9% of the 2040 emissions of 6.7 Gt under the baseline scenario. We also modelled a more-extensive scenario for the application of low carbon technologies with carbon capture and storage and renewable energy applied for all the production of newly-demanded electricity from 2025, and electric vehicles replacing all the newlyincreased oil fueled automobiles from 2030. In this case, the aggregated emissions of these emerging emitting countries would be 5.9 Gt, which is 811 Mt (12%) lower than the baseline scenario. Even with the rapid application of low-carbon technologies, the emission growth rate is higher than that under SSP1. This suggests that while new technologies can help to reduce the emissions of these countries, alone they are insufficient to enable them to achieve a "sustainable pathway". Uganda (Figure 4e) is also projected to experience slower growth from 2020 to 2024 even without the impact of COVID. Emissions under the default lockdown assumption fall by about 25% and recover to 96% of the baseline level by the end of the COVD period. There has been some spread of COVID since August 2020, following the loosening of the strict lockdown in July 2020. Nevertheless, the situation is much better than the African average, and the effectiveness of the initial lockdown strategy, means that Uganda may achieve a mild-lockdown pathway, at least no worse than the default lockdown scenario. In this situation and if the country continues increasing consumption of oil without applying low-carbon technologies, the post-COVID emissions will be around 15.4 Mt CO2 in 2040, compared to the 13.7 Mt emissions with LCT.
Peru (Figure 4f) is projected to experience a steady increase in growth from 2020 to 2024 in the absence of COVID. However, emissions under the default lockdown assumption fall considerably by about 40% although they recover to 98% of the baseline level by 2024; Despite applying strict lockdown measures since March 2020, Peru has been fighting one of the worst COVID outbreaks with over 820 thousand confirmed cases and more than 32 thousand deaths. By October 2020, the spread has yet to be controlled, and if the trend continues, Peru will probably maintain its strict lockdown strategies and its future CO2 emissions may decline substantially. In such circumstance, Peru's emissions will reach 68 Mt in 2040 under NPS, which is 4 years behind that of the baseline and mildest-lockdown assumption. With low-carbon technologies emissions could be reduced by 5.7% in 2040.

Discussions and Conclusion
Emerging emitters among developing countries have collectively contributed extremely little to the overall stock of CO2 in the atmosphere. However, they have come to the forefront of the growth of CO2 emissions over the past decade and will likely increasingly be so. Strong and sustained economic growth, crucial for poverty reduction, increases in population and heavy carbon energy consumption will drive significant emissions growth. Taking energy structure as an example, over the period 2010-2018, among the 34 countries that use coal in our sample of developing countries, 23 countries show a rising share of coal consumption in the energy mix and 29 countries increased their absolute consumption of coal. The impact of COVID is hitting developing countries hard and putting back progress on poverty reduction. The World Bank predicts that the COVID-19 pandemic could result in between 71 and 100 million people being pushed into extreme poverty 19 . There will, therefore, be a need to quickly revive growth in these economies, and their current dependence on traditional fossil fuels is likely to result in significant carbon emissions.
These countries are confronting the massive challenges of achieving inclusive economic development, contributing to climate change mitigation and adapting to rising global temperatures, changing precipitation and more extreme weather events. Indeed, these emerging emitters are the most vulnerable and least prepared to adapt to climate change. For these countries, climate change will undermine their ability to drive poverty reduction as it will constrain productivity growth, especially in agriculture, and requires scarce resources to be redirected towards adaptation. Costinot et al (2016), for example, compute that the impact of climate change on agricultural productivity alone will result in a decline in welfare equivalent to almost 4% of GDP in Uganda and over 6.5% of GDP in Vietnam. This assumes that trade and production patterns adjust to dampen the impact. If adjustment is constrained then losses could amount to more than 7.5% of GDP in Uganda and over 11 per cent in Vietnam.
These countries actions relating to emissions reduction will significantly influence the global effort to mitigate climate change. There is a large degree of diversity across these countries in terms of the size of national absolute CO2 emissions, the relationship between GDP growth and increases in CO2 emissions, the drivers of the emissions growth, the response to the COVID impact, and the impact of alternative post-COVID pathways. This requires country specific assessments and responses rather than common strategies defined for all the countries. Many of these countries are also already at the forefront of mitigation efforts in terms of enhancing the ambition of their Nationally Determined Contributions under the Paris Agreement 20 . In the post-COVID era, the outcomes from different pathways could lead to a difference of over 1 Gt in emissions from these countries.
Hence, to limit global warming well below 2 °C, the world needs to reduce emissions by 25% less than 2018 levels and emerging emitters have a significant role to play. This would be facilitated by measures in emerging emitters to adopt lower-carbon development pathways, including progress on accelerating changes to industrial structure, energy transformation and adoption of new production technologies. For example, in countries where industry drives emissions growth, efforts could focus on accelerating structural transformation, which in turn is essential for economic diversification and job creation; countries with increasing energy consumption as major drivers of emissions growth can explore ways to lower their emission intensity, through both technologies that improve energy efficiency and shifts towards low carbon sources of energy, such as, clean oil, gas, and renewable energy.
A global adoption of a "low carbon lifestyle" would lessen the carbon intensity of production in developing countries. Low-carbon technologies are a crucial means to limit the surging emissions. In our scenario analyses, adoption of low-carbon technologies can have a considerable influence on future emission reduction: with early application of CCS and renewable energy in the power sector and electric vehicles replacing the oil-fueled automobiles, the emerging emitters could reduce emissions by 600 Mt CO2 by 2040.
The challenge for the global community is to facilitate these economic transformations in ways that support sustained growth and poverty reduction. This can be achieved by improving access to the finance and knowledge necessary to support adoption of new technologies and the shift towards lower carbon intensity of growth. More advanced countries could assist developing countries by sharing energy-saving technologies and knowledge about renewable energy. Climate clubs have been identified as one solution to deliver coordinated climate mitigation (Nordhaus 2015;Paroussos et al. 2019), facilitating, for example, the technology diffusion that would lower the cost of mitigation in developing economies. More generally, simultaneously addressing the challenges of ending extreme poverty, achieving inclusive growth throughout the world and meeting climate goals will require cooperative solutions that integrate both the development needs and emission realities of developing countries.