Landmark United in Science report informs Climate Action Summit
New York, 22 September 2019 – The world’s leading climate science organizations have joined forces to produce a landmark new report for the United Nations Climate Action Summit, underlining the glaring – and growing – between agreed targets to tackle global warming and the actual reality.
The report, United in Science, includes details on the state of the climate and presents trends in the emissions and atmospheric concentrations of the main greenhouse gases. It highlights the urgency of fundamental socio-economic transformation in key sectors such as land use and energy in order to avert dangerous global temperature increase with potentially irreversible impacts. It also examines tools to support both mitigation and adaptation.
“The Report provides a unified assessment of the state of our Earth system under the increasing influence of anthropogenic climate change, of humanity’s response thus far and of the far-reaching changes that science projects for our global climate in the future. The scientific data and findings presented in the report represent the very latest authoritative information on these topics,” said the Science Advisory Group to the UN Secretary-General’s Climate Action Summit.
“It highlights the urgent need for the development of concrete actions that halt global warming and the worst effects of climate change.”
The Science Advisory Group is co-chaired by WMO Secretary-General Petteri Taalas and Leena Srivastava, former Vice Chancellor of TERI School of Advanced Studies. It comprises highly recognized and respected natural and social scientists, with expertise in different aspects of climate change, including on mitigation and adaptation.
The report, which was coordinated by the World Meteorological Organization, aims to present a “transparent envelope” of authoritative and actionable cutting-edge science.
The synthesis report consists of short summaries from contributing agencies: the World Meteorological Organization (WMO), Global Atmosphere Watch, the United Nations Environment Programme (UNEP), Global Carbon Project, the Intergovernmental Panel on Climate Change (IPCC), Future Earth, Earth League and the Global Framework for Climate Services. The synthesis is complemented by longer, individual reports, presented as a package to a high-level science event on 22 September and then to world leaders at the Climate Action Summit on 23 September.
Highlights from the report include:
Global Carbon Budget
Global Carbon Project
Carbon dioxide emissions grew 2% and reached a record high of 37 billion tonnes of CO2 in 2018. There is still no sign of a peak in global emissions, even though they are growing slower than the global economy.
Current economic and energy trends suggest that emissions will be at least as high in 2019 as in 2018. Global GDP is expected to grow at 3.2% in 2019, and if the global economy decarbonized at the same rate as in the last 10 years, that would still lead to an increase in global emissions.
Despite extraordinary growth in renewable fuels over the past decade, the global energy system is still dominated by fossil fuel sources. The annual increase in global energy use is greater than the increase in renewable energy, meaning the fossil fuel use continues to grow. This growth needs to halt immediately.
The net-zero emissions needed to stabilize the climate requires both an acceleration in use of non-carbon energy sources and a rapid decline in the global share of fossil fuels in the energy mix. This dual requirement illustrates the scale of the challenge.
Natural CO2 sinks, such as vegetation and oceans, which remove about half of all emissions from human activities, but will become less efficient at doing so. This underscores the need to reduce deforestation and expand natural CO2 sinks, particularly those in forests and soils that can be improved by better management and habitat restoration.
Intergovernmental Panel on Climate Change (IPCC)
Three IPCC Special Reports released in 2018 and 2019 assess complementary and specific aspects of climate change, ahead of the Sixth Assessment Report.
The Special Report on Global Warming of 1.5°C states that limiting warming to 1.5ºC is not physically impossible but would require unprecedented transitions in all aspects of society. There are clear benefits to keeping warming to 1.5 ºC compared to 2 ºC or higher. Every bit of warming matters.
Limiting warming to 1.5ºC can go hand in hand with reaching other world goals such as achieving sustainable development and eradicating poverty.
The Special Report on Climate Change and Land stressed that land is already under growing human pressure and climate change is adding to these pressures. At the same time, keeping global warming to well below 2ºC can be achieved only by reducing greenhouse gas emissions from all sectors including land and food.
“The report shows that better land management can contribute to tackling climate change, but land is not the only solution. Reducing greenhouse gas emissions from all sectors including energy is essential if global warming is to be kept as close as possible to 1.5ºC above pre-industrial levels.”
On 25 September 2019, the IPCC is due to release the Special Report on the Ocean and Cryosphere in a Changing Climate.
Future Earth and Earth League
Consolidated evidence reinforces human influence as the dominant cause of changes to the Earth system, in a new geological epoch, the Anthropocene.
Growing climate impacts increase the risks of crossing critical tipping points. These refer to thresholds that, if crossed, lead to far-reaching, in some cases abrupt and/or irreversible changes.
There is a growing recognition that climate impacts are hitting harder and sooner than climate assessments indicated even a decade ago.
As climate change intensifies, cities are particularly vulnerable to impacts such as heat stress and can play a key role in reducing emissions locally and globally.
Strategies for mitigation and for upscaling adaptive risk management are necessary going forward. Neither is adequate in isolation given the pace of climate change and magnitude of its impacts.
Only immediate and all-inclusive action encompassing: deep de-carbonization complemented by ambitious policy measures, protection and enhancement of carbon sinks and biodiversity, and efforts to remove CO2 from the atmosphere, will enable us to meet the Paris Agreement.
The synthesis report has been compiled by the World Meteorological Organization under the auspices of the Science Advisory Group of the UN Climate Action Summit 2019, to bring together the latest climate science related updates from a group of key global partner organizations – The World Meteorological Organization (WMO), UN Environment, Intergovernmental Panel on Climate Change (IPCC), Global Carbon Project, Future Earth, Earth League and the Global Framework for Climate Services (GFCS). The content of each chapter of this report is attributable to published information from the respective organizations.