Nature - Niklas Höhne, Michel den Elzen | Joeri Rogelj | Bert Metz | Taryn Fransen | Takeshi Kuramochi | Anne Olhoff | Joseph Alcamo | Harald Winkler | Sha Fu | Michiel Schaeffer | Roberto Schaeffer | Glen P. Peters | Simon Maxwell | Navroz K. Dubash
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| Women carry coal from an open-cast mine in Jharkand state in India. Credit: Kuni Takahashi/Getty |
The past decade of political failure on
climate change has cost us all dear. It has shrunk the time left for
action by two-thirds. In 2010, the world thought it had 30 years to
halve global emissions of greenhouse gases. Today, we know that this
must happen in ten years to minimize the effects of climate change.
Incremental shifts that might once have been sufficient are no longer
enough.
The further bad news is that, even taken together, the
proposed climate action by all countries is a long way from meeting this
requirement. Rather than halving emissions by 2030, countries’ climate
proposals will lead to a slight increase. Worse still, individual
countries are not on track to achieve commitments that were insufficient
from the outset and are now woefully inadequate.
The better news
is that more countries, regions, cities and businesses are implementing
the deep, rapid transformations that are urgently required. At scale,
these could achieve the collective climate goals that nations agreed in
Paris more than four years ago. There are lessons to be learnt from
places such as Costa Rica, Shenzhen in China and Copenhagen that have
made strides through the use of renewable energy and electrified
transport. The United Kingdom (together with 75 other parties) and
California have at least set ambitious goals to become carbon neutral,
which might send signals to industry even before supporting policies are
implemented. Meanwhile, 26 banks have stopped directly financing new
coal-fired power plants (see
go.nature.com/32uped2).
Much
is happening on the ground. The question is how to ramp up these
activities fast enough to keep warming to less than 1.5 °C above
pre-industrial levels.
Here we present a snapshot of the extent to
which nations’ individual pledges are inconsistent with their stated
collective goals. We also note some of the pockets of promise. We draw
our conclusions from a synthesis of all ten editions of the
Emissions Gap Report produced by the
United Nations Environment Programme (UNEP)
1–5.
Each year for the past decade, this report has examined the difference
between what countries have pledged to do individually to reduce
greenhouse-gas emissions, and what they need to do collectively to meet
agreed temperature goals — the ‘gap’.
Our analysis shows that the
gap has widened by as much as four times since 2010. There are three
reasons for this. First, global annual greenhouse-gas emissions
increased by 14% between 2008 and 2018
6.
This means that emissions now have to decline faster than was
previously estimated, because it is cumulative emissions that determine
the long-term temperature increase. Second, the international community
now agrees that it must ensure a lower global temperature rise than it
decided ten years ago, because climate risks are better understood. And
third, countries’ new climate pledges have been insufficient.
The
tenth anniversary of the report coincides with the 2020 milestone to
which countries agreed in Paris. They undertook to communicate or update
climate pledges, or ‘nationally determined contributions’, to the
UN Framework Convention on Climate Change conference (COP26) this November
in Glasgow, UK. Clearly, the promises must be overhauled — and then,
crucially, kept — if the yawning gap between ‘talk and walk’ is going to
close by 2030.
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| Electric taxis at a charging station in Shenzhen, China. Credit: Qilai Shen/Bloomberg/Getty |
Gap minder
The scope of the UNEP emissions
gap reports has evolved over time, in line with climate policy. So what
has changed during the past decade?
In the 2009 Copenhagen accord
7 and the 2010 Cancun agreement
8,
countries collectively pledged to limit warming to below 2 °C, and 73
countries individually pledged emissions targets for 2020. The 2015
Paris agreement, responding to mounting concern over the impacts of
climate change, tightened the collective temperature limit to “well
below 2 °C” and agreed “to pursue efforts to limit the temperature
increase to 1.5 °C”
9. Under the Paris deal, 192 parties individually pledged emissions targets, typically for 2030 (see ‘More and faster’).
 |
| Sources: Historical emissions: ref. 6; 2010 pledges and pathways: ref. 1; 2015 pledges and pathways: ref. 2. |
From 2010 to 2014, the gap reports projected the likely
difference in 2020 between the expected result of countries’ pledges and
the pathways towards 2 °C. The 2010 report documented a shortfall of
14%. Since 2015, the reports have forecast the expected shortfall in
2030 between the countries’ pledges and progress towards both 1.5 °C
(current shortfall of 55%) and 2 °C (current shortfall of 25%; see ‘More
and faster’). The report also examines the policies that countries are
implementing domestically.
Had serious climate action begun in
2010, the cuts required to meet the emissions levels for 2 °C would have
been around 2% per year, on average, up to 2030. Instead, emissions
increased. Consequently, the required cuts from 2020 are now more than
7% per year on average for 1.5 °C (close to 3% for 2 °C).
The time window for halving global emissions has also
narrowed drastically. In 2010, it was 30 years; today, it is 10 years
for 1.5 °C (25 years for 2 °C). Although many reports, scientists and
policymakers continue to discuss rises of 2 °C, it must be emphasized
that, in 2018, the Intergovernmental Panel on Climate Change reported
that warming of more than 1.5 °C would be disastrous
10.
Countries
are not even on track to achieve their now plainly inadequate 2015
pledges. Of the G20 countries, seven (Australia, Brazil, Canada, Japan,
South Korea, South Africa and the United States) need to implement
existing policy or roll out new measures. (The United States has begun
the process of withdrawing from the Paris agreement, and will leave in
November.) Russia and Turkey have set themselves unambitious targets
that they can meet without new policies.
Since 2015, estimated
global emissions in 2030 have decreased by only 3%. For the leading
seven emitters, 2030 estimates have slightly decreased, flatlined or
increased (see ‘The seven top emitters’).
 |
| Comparison of the 2015 and 2019 UNEP Emissions Gap Report2,20 and other sources21–25 provides information about changes in current policy projections for the leading emitters. Uncertainties for each estimate are large. See Supplementary Information for details. |
No single model can predict the future, and such analyses by
necessity exclude the most recent developments. Nevertheless, it is
clear that, collectively, current policies will not limit global warming
to well below 2 °C, let alone 1.5 °C, as agreed in Paris.
Clearly,
the annual audit of the emissions gap has not altered poor performance.
The gap concept has nonetheless proved useful. The reports and numbers
have continuously informed the UN climate summits
11 and the emissions gap was noted as a serious concern when parties were adopting the Paris agreement
9.
Transformative action
Fundamental
policy transformations have begun to appear in some sectors, countries,
regions, cities and businesses over the past ten years. These
innovations seek to achieve the UN’s Sustainable Development Goals
(SDGs), including climate ones. Slashing emissions now requires ‘leaving
no one behind’.
To recognize, monitor and understand these advances, the gap reports have included examples. Some are discussed here.
Ambitious action
Most encouragingly, a wealth of agile nations, regions, cities and
businesses have promised or made radical changes since the Paris
agreement (see ‘Action gap’ and Supplementary Information. See also
go.nature.com/2t22tth).
At the last count, net-zero emissions goals have been set or are being
considered by 76 countries or regions (the European Union is the
largest) and 14 sub-national regions or states (the largest being
California); some locations have begun implementation. Together, these
places account for about 21% of global greenhouse-gas emissions
12,13.
 |
| Sources: 2017 emissions: refs 12,13; 2017 Energy production: ref. 14. |
Fifty-three countries and 31 states and regions have
explicitly committed to an emissions-free electricity sector. Seven
additional countries have done so implicitly by aiming for net-zero
greenhouse-gas emissions. Together, these account for around 18% of
global electricity generation
14.
Twenty-one countries, 5 regions and more than 52 cities have committed
to make all vehicles emissions-free. Individual examples also exist for
sectors in which reaching zero emissions was thought to be difficult,
such as heavy industry and aviation. Steel giants ThyssenKrupp in Essen,
Germany, and SSAB in Stockholm are aiming for zero-emissions steel
production by 2050 and 2045, respectively. The building-materials
company Heidelberg Cement, headquartered in Germany, is aiming for
zero-emissions cement production by 2050. For aviation, Norway and
Scotland hope to make short-haul and domestic flights zero emissions by
2040.
Renewables
Costs of renewable energy are falling faster than expected
15.
Renewables are currently the cheapest source of new power generation in
most of the world. Solar and wind power will be financially more
competitive than will existing coal plants by next year
15. These cost declines, and those of battery storage, are opening up possibilities for large-scale, low-carbon electrification.
Coal consumption
The rise of renewable energy can –
must – facilitate a move away from coal. Emerging economies that depend
on coal, such as China and India, have begun to address consumption by
adjusting the fuel’s price, capping its consumption, reducing plans for
new coal-fired power plants and supporting renewables. Much more must be
done, and quickly — while addressing poverty, energy access and
urbanization
16–18.
UN SDGs
Actions to reduce greenhouse-gas emissions are essential for achieving
food security, healthy lives and many other SDGs, as confirmed by a
growing body of research
10,19. For example, renewable energy cuts air pollution, and improves health and energy security compared with fossil fuels.
Closing the gap
These
few success stories must be scaled up and mirrored with progress in
every sector. The fact that reductions in greenhouse-gas emissions are a
prerequisite to achieving sustainable development must propel action.
The
gap is so huge that governments, the private sector and communities
need to switch into crisis mode, make their climate pledges more
ambitious and focus on early and aggressive action. Otherwise, the Paris
agreement’s long-term goals are out of reach. We do not have another
ten years.
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