CO2 emissions

GeoSciences Column: The dirty business of shipping goods by sea

“Above the foggy strip, this white arch was shining, covering one third of the visible sky in the direction of the ship's bow,” he explains. “It was a so-called white, or fog rainbow, which appears on the fog droplets, which are much smaller then rain droplets and cause different optic effects, which is a reason of its white colour.”

Shipping goods across the oceans is cost-effective and super-efficient; that’s why over 80% of world trade is carried by sea (according to the International Maritime Organisation). But the shipping industry also contributes significant amounts of air pollutants to marine and coastal environments.

A new study, published in the EGU’s open access journal Earth System Dynamics, reports on concentrations of sulphur, nitrogen, and particulate matter (PM), from 2011 to 2013, in the Baltic and North Seas – one of the busiest shipping routes in the world. The study aims to provide policy-makers with better knowledge about how shipping impacts local environments. The end-goal being better industry regulations and technology to make shipping more sustainable in the long-term.

The reality of shipping goods by sea

In the past two decades reduction pledges, like the Paris Climate Accord, and strict regulation have driven down air pollutants from land-based emissions across Europe, but greenhouse-gas emissions from the shipping industry are not subject to as strict international protocols.

And that’s a problem.

It is estimated that there are about half a million ships in operation at present, which together produce almost one billion tonnes of carbon dioxide each year (that’s more than Germany emits in the same period!). Over the past 20 years, emissions of pollutants from shipping in the Baltic Sea and North Sea have increased.

Worryingly, economic growth in the region means shipping is only set to increase in the future. In fact, the European Commission predicts that shipping emissions will increase between 50% and 250% by 2050.

Why should you care?

While cruising the high seas, ships emit a dangerous cocktail of pollutants. When burnt, their fuels emit sulphur dioxide and as ship engines operate under high pressure and temperature, they also release nitrogen oxides. Combined, they are also the source of particulate matter of varying sizes, made up of a mixture of sulphate (SO4), soot, metals and other compounds.

The authors of the Earth System Dynamics paper, led by Björn Clareman of the Department of Earth Sciences at Uppsala University, found that international shipping in the Baltic Sea and the North Sea was responsible for up to 80% of near-surface concentrations of nitric oxide, nitrogen dioxide and sulphur dioxide in 2013.

Total emissions of SOx and deposition of OXS (oxidized sulphur) from international shipping in the Baltic Sea and North Sea in 2011. From B.Claremar et al., 2017.

In addition, the team’s simulations show that PM from shipping was distributed over large areas at sea and over land, where many people will be exposed to their harmful effects. The highest concentrations are found along busy shipping lanes and big ports. In total, shipping was responsible for 20% of small sized PM (known as PM2.5) and 13% of larger particles (PM10) during the studied period.

These pollutants have harmful effects on human health: It is thought that living close to the main shipping lanes in the Baltic Sea can shorten life expectancy by 0.1 to 0.2 years. Sulphur oxides in particular, cause irritation of the respiratory system, lungs and eyes; while a 2007 study estimated that PM emissions related to the shipping industry cause 60,000 deaths annually across the globe.

Environmentally, the effects of shipping pollution are concerning too. Deposition of nitrate and sulphate causes the acidification of soils and waters. The brackish waters of the Baltic Sea make them highly susceptible to acidification, threatening diverse and precious marine ecosystems.

The current problem

Legislating (and then monitoring and enforcing) to limit the negative impact of shipping emissions is tricky given the cross-border nature of the industry. For instance, currently, there is no international regulation for the emission of PM. However, the International Maritime Organisation’s (as well as others; see Claremar, B., et al., 2017 for details of all regulations) does impose limits on sulphur and nitrogen emissions from ships (in some parts of the world).

Low-sulphur fuels and switching to natural gas are an effective way to control emissions. However, operators can also choose to fit their vessels with an exhaust gas treatment plant, or scrubber, which uses sea water to remove sulphur oxides – the by-products of high-sulphur fuels. So called open-loop scrubbers release the dirty exhaust water back into the ocean once the tank is cleaned. The practice is known to increase ocean acidification globally, but particularly along shipping lanes.

As of 2021, the transport of goods via the North and Baltic Seas will be subject to the control of nitrogen and sulphur emissions, which could decrease nitrogen oxide emissions by up to 80%. However, the study highlights that the continued use of scrubber technology will significantly offset the benefits of the new legislation. If cleaner alternatives are not implemented, total deposition of these harmful particles may reach similar levels to those measured during the 1970s to 1990s, when shipping emissions were largely unregulated.

By Laura Roberts Artal, EGU Communications Officer


Those who have an interest in this subject might want to contribute an EU Public consultation on the revision of the policy on monitoring, reporting and verification of CO2 emissions from maritime transport. The International Maritime Organisation (IMO) adopted the legal framework for the global data collection system (IMO DCS) in July 2017. This Consultation is now reviewing the situation and would like input on things such as the monitoring of ships’ fuel consumption, transparency of emission data and the administrative burden of the new system. While the Consultation is not specifically aimed toward scientists, it may interest EGU researchers who are working in the marine, climate and atmospheric sciences sectors.


Refences and resources

Claremar, B., Haglund, K., and Rutgersson, A.: Ship emissions and the use of current air cleaning technology: contributions to air pollution and acidification in the Baltic Sea, Earth Syst. Dynam., 8, 901-919,, 2017.

Lower emissions on the high seas. Nature, 551, 5–6, https://doi:10.1038/551005b, 2017

Corbett, J. J., Winebrake, J. J., Green, E. H., Kasibhatla, P.,Eyring, V., and Lauer, A.: Mortality from ship emissions: a global assessment, Environ. Sci. Technol., 41, 8512–8518, 2007.

Dashuan, T., and Shuli, N.: A global analysis of soil acidification caused by nitrogen addition, Environ. Res. Lett., 10, 024019, https://doi:10.1088/1748-9326/10/2/024019, 2015

What is Ocean Acidification? Ocean Facts by NOAA

Reducing emissions from the shipping sector, Climate Action by the European Commission

GeoPolicy: A new vehicle emissions test to be introduced, say EU’s top scientists

Inspector testing vehicle emissions

Last year the European Commission appointed a panel of world leading scientists to advise on key science policy issues. In November, the panel issued their first recommendation report focusing on COvehicle emissions. The month’s GeoPolicy post takes a closer look at this high-level advisory panel and the recommendations they have published.


In 2015, the Scientific Advice Mechanism (SAM) was established by the European Commission (EC) to improve research communication to policy officials. Previously, a Chief Scientific Advisor served this process, but after the position was discontinued in 2014 a crater was left in providing evidence-based policy in Europe. In response, EC President Jean-Claude Juncker, established SAM, which centres around a high-level panel of scientific experts who publish reports of topics of societal importance. These topics are chosen by the EC or suggested by the panel members themselves. SAM’s overall structure was covered in a previous GeoPolicy post entitled ‘GeoPolicy: 8 ways to engage with policy makers‘.

The panels’s first report, entitled ‘Closing the gap between light-duty vehicle real-world COemissions and laboratory testing’1, was commissioned in the wake of the Volkswagen NOemissions scandal in 2015. The report aimed to assess the scientific basis for improving measurements of light duty vehicle CO2 emissions, which approaches could be considered, and what additional scientific and analytical work would be needed to implement these tests.

The major findings say that developing further emissions testings, in both the laboratory and within the vehicles themselves, would significantly decrease the gap in measured levels. This test, known as the Worldwide Harmonised Light vehicles Test Procedure, will be a tougher standard for car manufacturers to adhere to and aims to be introduced across the EU in September 2017. In addition, a ban in awarding certificates to cars who have not been tested using the new method will be implemented. Finally, SAM’s panel recommend a review of the new procedure in 5 years to assess the improvements2.

SAM’s panel consists of 7 members (listed below). The geosciences are (loosely) represented by the newest panel member, Carina Keskitalo, a Professor of Political Science at the Department of Geography and Economic History at Umeå University. She researches into natural resource-use policy, in particular forestry and climate change adaptation policy. She replaced the UK Met Office’s chief scientist, Dame Julia Slingo, who served as a SAM member for one year.

High level group members:

  • Janusz Bujnicki – Professor, Head of the Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology, Warsaw (biology);
  • Pearl Dykstra – Professor of Sociology, Erasmus University Rotterdam (social science);
  • Elvira Fortunato – Deputy Chair – Professor, Materials Science Department of the Faculty of Science and Technology, NOVA University, Lisbon (material science);
  • Rolf-Dieter Heuer – Former Director-General of CERN (particle physics);
  • Carina Keskitalo – Professor, Department of Geography and Economic History (land-use and climate change);
  • Cédric Villani – Director, Henri Poincaré Institute, Paris (mathematics);
  • Henrik C. Wegener – Chair – Executive Vice President, Chief Academic Officer and Provost, Technical University of Denmark (epidemiology / microbiology).

The group aims to publish its second recommendation report on cybersecurity before the end of the year.


Sources / Additional reading

[1] – The SAM CO2 emissions report

[2] – ScienceBusiness: COtest is a clear step forward

[3] –  The Scientific Advice Mechanism

IPCC report ‘unprecedented changes’ in climate, urging policymakers to take action

“Human influence on the climate system is clear” was the key message from the report on the physical science of climate change from the Intergovernmental Panel on Climate Change (IPCC).

“We have come a long way since the first IPCC report was published in 1990,” a statement reiterated throughout the press conference for the release of the report. The IPCC were keen to register the significance of the work and progress made in this report – an “assessment of a string of assessments from 1990,” according to Thomas Stocker, Co-Chair for Working Group I, reporting on the physical science basis of climate change. The fourth IPCC assessment published in 2007 was the first report to state that “warming of the climate system is unequivocal” and that “most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.”

In the fifth report, this message is heightened. Since the 1950’s many of the changes observed and analysed in this report have been unprecedented including warming of the atmosphere and ocean, diminishing amounts of snow and ice, rising sea levels, and increases in the concentrations of greenhouse gases. With 259 lead authors citing 9200 papers in the report, two thirds of which have been published since 2007, the fifth assessment presents a strong message to policymakers across the world. Incredibly, this feat of scientific work has been approved and agreed upon by 110 governments across the world, with 1089 reviewers consisting of scientists, the public and governments from 55 of those countries offering a staggering 54,677 comments on the physical science basis report. Almost every word was commented on, disputed and discussed to come up with 18 headline messages – a first for the IPCC reports – that stated in simple language the report’s key outcomes.

“If you look at temperature, it is red” stated Stocker in a press conference, describing one of several key images from the IPCC policymaker summary.

Observed change in average surface temperature 1901-2012 from IPCC Working Group I summary for policymakers (SPM 28).

Observed change in average surface temperature 1901-2012 from IPCC Working Group I summary for policymakers (SPM 28).

This simple statement with clever wordplay not only elicits a global increase in surface temperature but also danger. Our planet is warming, and humans are the culprit. He goes on to say “…each of the last three decades has been successively warmer at the Earth’s surface than any preceding decade since 1850…Global surface temperature change for the end of the 21st century is likely to exceed 1.5°C relative to 1850 to 1900 for all RCP scenarios.” RCP stands for representative concentration pathways, four greenhouse gas concentration trajectory models used by the IPCC in its fifth report.

“In the Northern Hemisphere, 1983–2012 was likely the warmest 30-year period of the last 1400 years.” For the fifth assessment the IPCC have gone to great lengths not only to ensure consistency and reliability in scientific data and consensus, but also to outline the key points from their summary for policymakers: the use of simple language to describe the data that does not include hype or headlines but instead simple scientific language.

The report also highlights the increase in global mean sea level rise, with a key headline stating “…the rate of sea level rise since the mid-19th century has been larger than the mean rate during the previous two millennia (high confidence). Over the period 1901–2010, global mean sea level rose by 0.19 [0.17 to 0.21] m”.

In each of the IPCC’s four RCPs it was clear that the higher the cumulative carbon emissions, the warmer it gets.

Cumulative total anthropogenic CO2 emissions from 1870 (GtCO2 ) from IPCC Working Group I summary for policymakers (SPM 36).

Cumulative total anthropogenic CO2 emissions from 1870 (GtCO2 ) from IPCC Working Group I summary for policymakers (SPM 36).

The summary for policymakers states “…cumulative emissions of CO2 largely determine global mean surface warming by the late 21st century and beyond”, (above), “Most aspects of climate change will persist for many centuries even if emissions of CO2 are stopped. This represents a substantial multi-century climate change commitment created by past, present and future emissions of CO2.”

Dominique Raynaud, review editor of chapter five (on palaeoclimatology) of the report and officer on the EGU Climate: Past, Present and Future Division in an interview with the EGU Educational Fellow commented on the most important aspect of this report: “For the first time the scientific community has defined a set of 4 [RCP] scenarios which represent a range of 21st century climate policies. Only one scenario suggests that the global mean temperature change for the end of the 21st century will not exceed 2°C.”

Global average surface temperature change estimated from present to 2100 (°C), from IPCC Working Group I summary for policymakers (SPM 33).

Global average surface temperature change estimated from present to 2100 (°C), from IPCC Working Group I summary for policymakers (SPM 33).

Raynaud went on to say “With this scenario, we still have a hope to keep [to the] reasonable expected warming for this century…policymakers should obviously consider such a possibly.”

In some ways, the outcomes of this report are a repetition of what the public have already been hearing: humans are influencing climate change. But what is crucial to note about this 5th assessment report is the huge consensus among scientists, public and governments about this statement.

“This is not about ideology, this is not about self-interest” was a quote from Achim Steiner, the head of the UN’s environment programme, UNEP – a comment that will resonate with many through the ‘unequivocal’ status of the report’s conclusions – and a statement that Stocker echoed later “it threatens our planet, our only home,” clearly urging policymakers across the globe to take combined action on climate change.

By Jane Robb, EGU Educational Fellow


IPCC Working Group I session report for 5th Assessment Report (summary for policymakers)

IPCC 5th Assessment Report (full)

IPCC 4th Assessment Report (full)