United in Science report 2020: A multi-organization high-level compilation of the latest climate science information

Full Text Sharing

Building on last year’s report, the United in Science 2020 report highlights rising global emissions and the irreversible impacts of climate change. These negatively effect our oceans and seas, ecosystems and economies, water resources and our human well-being and health. The report outlines how the COVID-19 pandemic has impeded our ability to monitor these changes through the global observing system.

The United in Science report is a collection of key climate science findings by leading global organizations in the field of climate change research. The report was first launched in 2019.

The report is coordinated by the World Meteorological Organization (WMO), with contributions from the Global Carbon Project, the Intergovernmental Panel on Climate Change, the Intergovernmental Oceanographic Commission of UNESCO, the UN Environment Programme and the UK’s Met Office.



The United in Science 2020 Report has been compiled by the World Meteorological Organization (WMO) under the direction of the United Nations Secretary-General to bring together the latest climate science related updates from a group of key global partner organizations – WMO, Global Carbon Project (GCP), UNESCO Intergovernmental Oceanographic Commission (UNESCO-IOC), Intergovernmental Panel on Climate Change (IPCC), UN Environment Programme (UNEP) and the Met Office. The content of each chapter is attributable to each respective organization.


Foreword by António Guterres, Secretary-General of the United Nations

António Guterres, Secretary-General of the United Nations
António Guterres, Secretary-General of the United Nations

This has been an unprecedented year for people and planet. The COVID-19 pandemic has disrupted lives worldwide. At the same time, the heating of our planet and climate disruption has continued apace. Record heat, ice loss, wildfires, floods and droughts continue to worsen, affecting communities, nations and economies around the world. Furthermore, due to the amount of greenhouse gases emitted in the past century, the planet is already locked into future significant heating.

The solution to slowing down the rate of global temperature rise and keeping it below 1.5°C is for nations to dramatically cut emissions, with the aim of achieving carbon neutrality by 2050. While emissions fell during the peak of the pandemic confinement measures, they have already mostly recovered to within 5 per cent of the same period in 2019 and are likely to increase further. This report stresses that short-term lockdowns are no substitute for the sustained climate action that is needed to enable us to meet the goals of the Paris Agreement on Climate Change.

Never before has it been so clear that we need long term, inclusive, clean transitions to tackle the climate crisis and achieve sustainable development. We must turn the recovery from the pandemic into a real opportunity to build a better future.

In order to do that, governments need consistent and solid science, backed by the strong collaboration of scientific institutions and academia, to underpin policy decisions that can tackle the greatest challenges of our time.

This report by the United Nations and global scientific partner organizations, provides an update one year from the first United in Science report, which was launched to inform the United Nations Climate Action Summit 2019.

United in Science 2020 presents a unified assessment of the state of our Earth system, detailing how emissions have evolved in 2020, and providing projections for the critical years ahead. The report further addresses key thematic issues on the front lines of climate change, such as water, oceans and the cryosphere and highlights the vulnerability of land-based, marine and air observing systems which are essential to underpin our understanding of climate science.

We need science, solidarity and solutions to tackle both the COVID-19 pandemic and the climate crisis. I urge leaders to heed the facts contained in this report, unite behind the science and take urgent climate action to set a path towards a safer, more sustainable future for all.

António Guterres, Secretary-General of the United Nations



Foreword by Prof. Petteri Taalas, Secretary-General of the World Meteorological Organization

Prof. Petteri Taalas, Secretary-General of the World Meteorological Organization
Prof. Petteri Taalas, Secretary-General of the World Meteorological Organization

2020 has been a remarkable year in many ways. Not least of course because of the global pandemic, impacting lives and livelihoods across the planet like never before. This year has also been remarkable in terms or our climate, continuing the trend we have seen in recent decades.

Greenhouse gas concentrations - which are already at their highest levels in 3 million years - have continue to rise, reaching new record highs this year. Meanwhile, large swathes of Siberia have seen a prolonged and remarkable heatwave during the first half of 2020, which would have been almost impossible without anthropogenic climate change. And now 2016–2020 is set to be the warmest five year period on record. This report shows that whilst many aspects of our lives have been disrupted in 2020, climate change has continued unabated.

Despite the challenges that 2020 has brought, the scientific commuity have continued their important work at pace. Collaborating in new and innovative ways with an important mission in mind, to provide a robust, authoritative scientific evidence base for decision makers around the world.

United in Science 2020 delivers on this mission, presenting the very latest scientific data and findings related to climate change, relevant to this unprecedented year. This report is an example of the international scientific community’s commitment to strategic collaboration in order to advance the use of scientific evidence in global policy, discourse and action.

I would like to thank the many expert teams from our scientific partners in creating this report – Global Carbon Project, the Intergovernmental Panel on Climate Change, UNESCO-IOC, UN Environment Programme and the Met Office. Thanks to their excellent collaboration, the climate science community are able to unite to provide policymakers all over the world with the latest essential information in these unprecedented times.

Prof. Petteri Taalas, Secretary-General of the World Meteorological Organization


Key Messages

United in Science 2020


Greenhouse Gas Concentrations in the Atmosphere - Global Atmosphere Watch (GAW)

WMO LogoConcentrations of the major greenhouse gases, CO2, CH4, and N2O continued to increase in 2019 and 2020. Overall emissions reductions in 2020 will lead to a small reduction in the annual increase of the atmospheric concentrations of long-lived greenhouse gases. Sustained reductions in emissions are required to stabilize global warming.


Global Fossil CO2 Emissions

Global Carbon ProjectGlobal fossil fuel emissions in 2019 were slightly higher than in 2018, with record emissions of 36.7 Gigatonnes (Gt = billion metric tonnes) of carbon dioxide (CO2) (Figure 1). Emissions growth has slowed to around 1% per year in the last decade, down from 3% annual growth during the 2000s. The near-zero growth seen in 2019 gives hope that the CO2 emissions trend is stabilizing, and that a decline is on the horizon. Nonetheless, stable or slightly declining emissions were seen earlier in the 2010s and, disappointingly, have not endured. Total fossil CO2 emissions are now 62% higher than emissions at the time international climate negotiations began in 1990.


Global Climate in 2016–2020

2016–2020 set to be warmest five-year period on record

WMO LogoThe average global mean surface temperature1 for 2016–2020 (2020 data are based on averages January to July) will be among the warmest of any equivalent period on record (Figure 1). It is currently estimated to be 1.1 °C (±0.1°C) above pre-industrial2 (1850–1900) times and 0.24 °C (±0.10°C) warmer than the global mean surface temperature for 2011–2015.


The Ocean and Cryosphere in a Changing Climate

Why do changes in the ocean and cryosphere matter? (IPCC, 2019)

IPCCThe global ocean covers 71% of the Earth surface. Around 10% of Earth’s land area is covered by glaciers or ice sheets. The ocean and cryosphere support unique habitats and are interconnected with other components of the climate system through global exchange of water, energy and carbon.


Water and Cryosphere

Climate and water resources

WMO LogoThe changes that are happening in our climate system have started to impact and will have more pronounced impacts on our planet. The United Nations World Water Development Report (UNESCO, 2019) lists three key water related impacts of a changing climate: 1. Increases in water-related disasters, 2. Increases in areas suffering from water stress, and 3. Increases in poor water quality related fatalities. Currently, 90% of the impact of natural disasters is water related (Figure 1).


Global Climate in 2020–2024 – WMO Global Annual to Decadal Climate Update

WMO Met officeThe WMO Lead Centre for Annual to Decadal Climate Prediction produces a summary of annual to decadal predictions for the coming five years. These predictions are the best estimate of the near term climate as they are based on ten of the world’s leading decadal prediction systems from WMO-designated Global Producing Centres and non-designated contributing centres and include 100 multiple realizations with both observed initial conditions of the type used in seasonal prediction and boundary forcing used to drive long-term climate projections. The predictions do not include any changes in emissions due to COVID-19 effects and they assume that no major volcanic eruptions occur in the period until 2024.


Emissions Gap

The emissions gap is larger than ever

UNEPThe United Nations Environment Programme (UNEP) issued its tenth Emissions Gap Report in late 2019 and the preparations for the 2020 report are on track for December 2020. The reports assess the difference between where global greenhouse gas (GHG) emissions are heading and where they need to be for the world to get on track to keeping global warming within the agreed goals in the Paris Agreement.


Earth System Observations during COVID-19

COVID-19 impacts the observing system and our ability to forecast weather andpredict climate change

UiS Earth Observing System CovidThe COVID-19 pandemic has produced significant impacts on the global observing systems for weather, climate, water and ocean health, which in turn have affected the quality of forecasts and other weather, climate and ocean-related services.

Lead authors and contributors

Overall coordination and editing by WMO: Jürg Luterbacher, Laura Paterson, Kate Solazzo and Sylvie Castonguay (Editor).

Greenhouse Gas Concentrations in the Atmosphere (Global Atmosphere Watch, GAW): Oksana Tarasova (WMO), Alex Vermeulen (Lund University, Sweden).

Global Fossil CO2 emissions (GCP): Josep G Canadell (CSIRO, Australia), Robert B Jackson (Stanford University, USA), Robbie M Andrew (CICERO, Norway), Pierre Friedlingstein (University of Exeter, UK), Matthew W Jones (University of East Anglia, UK), Corinne Le Quéré (University of East Anglia, UK), Glen P Peters (CICERO, Norway), Benjamin Poulter (NASA, USA), Marielle Saunois (LSCE-IPSL, France), Ann Stavert (CSIRO, Australia).

Global Climate in 2016-2020 (WMO): Omar Baddour (WMO), Anny Cazenave (Laboratoire d’Etudes en Géophysique et Océanographie Spatiales, Centre National d’Etudes Spatiales and Observatoire Midi-Pyrénées, France), Matthias Huss (ETH Zurich, Switzerland), John Kennedy (UK Met Office, UK), Peter Siegmund (Royal Netherlands Meteorological Institute, KNMI, Netherland), Blair Trewin (Bureau of Meteorology, BoM, Australia), Markus Ziese (Deutscher Wetterdienst, DWD, Germany).

Ocean and Cryosphere in a Changing Climate (IPCC): Valérie Masson-Delmotte (IPCC WGI co-chair), with inputs from Sarah Connors (WGI TSU, University Paris Saclay, France), Panmao Zhai (IPCC WGI co-chair), Hans-Otto Pörtner (IPCC WGII co-chair) and Debra Roberts (IPCC WGII co-chair).

Water and Cryosphere (WMO): Johannes Cullmann (WMO), Rodica Nitu (WMO), Lijuan Ma (WMO), Bruce Stewart (WMO), Thomas Lavergne (Norwegian Meteorological Institute, Norway), Petra Heil (Australian Antarctic Division, Australia), Tandong Yao (ITPR-CAS, Institute for Tibetan Plateau Research – Chinese Academy of Sciences, China).

Global Climate in 2020–2024 (WMO Global Annual to Decadal Climate Update, led by UK Met Office): Adam Scaife (UK Met Office), Leon Hermanson (UK Met Office), Doug Smith (UK Met Office)

Emissions Gap (UNEP): Anne Olhoff (UNEP DTU Partnership), John Christensen (UNEP DTU Partnership), Maarten Kappelle (UNEP), Jian Liu (UNEP).

Earth System Observations during COVID-19 (UNESCO-IOC and WMO): Emma Heslop (UNESCO-IOC), Albert Fischer (UNESCO-IOC), Salvatore Arico (UNESCO-IOC), Vladimir Ryabinin (UNESCO-IOC), Valentin Aich (WMO), Anthony Rea (WMO), Dean Lockett (WMO), Timo Pröscholdt (WMO).

Position: Co -Founder of ENGAGE,a new social venture for the promotion of volunteerism and service and Ideator of Sharing4Good

Add new comment

Filtered HTML

  • Web page addresses and e-mail addresses turn into links automatically.
  • Allowed HTML tags: <a> <em> <strong> <cite> <blockquote> <code> <ul> <ol> <li> <dl> <dt> <dd>
  • Lines and paragraphs break automatically.

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.