Data source
Mace Head Research Station

Weekly average
last updated: 13/09/2016

Threat level

Unless this unprecedented increase is slowed down, models show the balance in a highly complicated structure of climate systems will be tipped and a series of chain reactions will set off.

CO2 Record

CO2 levels are subject to seasonal variability and are currently rising year on year. This is the highest value measured so far at the Mace Head facility:


Measured on: 14/03/2015

If you can not measure it, you can not improve it.

- Lord Kelvin

Main cause of climate change

If you’ve heard about climate change, you’ve heard about its main cause: carbon. But what is it? Carbon dioxide (CO2) is the main heat-trapping gas in the layer of gases surrounding our planet.

Natural occurring levels have seen a  rapid increase since humans started pumping it into the atmosphere in large volumes. We started doing this during the industrial revolution, which kicked-off around 1750.

Known as the atmospheric level of CO2, it is monitored through a global network of measurement stations where scientists measure the amount of CO2 in Earth’s atmosphere as parts per million (PPM).

If you check the meter above you’ll notice it has been rising year-on-year. The levels are subject to seasonal variability due to the natural breathing cycles of Earth’s biosphere.

This website uses CO2 measurements from the Mace Head research station, based on the west coast of Ireland.

Climate Change and Global Warming

Never before has our planet faced a change in its climate as abruptly as now. A rapid, unprecedented build-up of CO2 – as well as other so-called greenhouse gasses – in our planet’s atmosphere is causing more heat emitted by the sun to be trapped on Earth. This is causing a rise in the average temperatures around the world, known as global warming.

Although the rise is just a few degrees, the climate change repercussions will be massive if we don’t act. Scientific models show a few degrees will tip the balance in a highly complicated structure of climate systems and set off an series of chain reactions. As a result, we are already seeing more extreme weather – hot and cold, wet and dry – and a rise in sea levels.

Human Activities

Human activities such as the burning of fossil fuels have been releasing the gaseous forms of solid carbon deposits like coal – built up over millions of years – into the atmosphere at an unprecedented rate.

A wide range of human actions are directly responsible for emitting CO2, in addition to that activities like cutting down forests are decreasing Earth’s natural ability to remove CO2 from the atmosphere through photosynthesis.

The History of CO2 Measurement

An American scientist based in Hawaii – Charles Keeling – was one of the first persons to take an interest in the build-up of CO2 in our atmosphere. We now understand that this accumulation of CO2 is causing climate change.

He initiated the measurement of CO2 on Hawaii, a pollution free environment in the Pacific, in 1958 and soon discovered a trend.

Keeling and his team established that a yearly increase in CO2 levels matched the amount of fossil fuels burned by humans.

To find out CO2 levels going back in time, scientists have since drilled into ancient ice sheets and have measured the CO2 trapped in air bubbles, mapping out the history of carbon levels going back hundreds of thousands of years.

Mace Head

Historically, the Mauna Loa laboratory on Hawaii has been one of the primary measurement locations around the world due to its remoteness in the Pacific.

In Europe, the Mace Head measurement station on the west coast of Ireland also provides an excellent environment with fresh unpolluted winds coming in from the Atlantic which can be compared to the winds coming in from the continent.

France-based Laboratoire des Sciences du Climat et de l’Environnement, through support from CNRS, CEA and OVSQ in France, leads the CO2 measurement operations at Mace Head, in collaboration with NUI Galway’s Centre for Climate and Air Pollution Studies (C-CAPS), the Irish Environmental Protection Agency, and the University of Bristol through the Department of Energy & Climate Change in the UK.

Mace Head has been one of the demonstration sites of the Integrated Observation System (ICOS) program of long-term greenhouse gas measurement in Europe since 2011. The measurement programme itself has been running since the late 1980s.

What do we do about it?

Now that we have realised that high levels of CO2 – along with a few other greenhouse gases like methane – are a threat to our way of life, scientists, businesses and governments around the world are working together to take action against climate change.

Around the world, people are coming up with innovative ways to stop the increase in the world’s production of CO2 and to build a new carbon-free economy, while helping humans adapt to some of the climate change that’s already become unstoppable.

Climate-KIC brings together




Policy Makers


People working together in Climate-KIC, and organisation launched by the European Union, collaborate to find new ways to drastically bring down CO2 emissions to stop further global warming, to find innovative ways to deal with impact of climate change that is already occurring and to create growth a jobs in Europe for generations go come.

Build your own application

The Mace Head CO2 data feed

What’s in the data feed

CO2 measurements at the Mace Head measurement station are performed with two cavity ring-down spectroscopy (CRDS) analysers. Both instruments are regularly calibrated against four standards which have been themselves calibrated in the international reference scales (WMO).

The CO2 data set provided in this project is calculated from the weekly running mean of marine measurement at Mace Head. In order to obtain the weekly average we take the hourly average measurement and filter it depending on wind speed, wind direction, standard deviation of the measurement and the duration of the marine event (Ramonet et al., Tellus-B, 201O).

Once we only have marine data for the two instruments in Mace Head we do the completion of the first instrument (41) with the available measurement of the second instrument (54). After that we calculate the weekly average at two digits and we assign the result to the first day of the week.

Are you using the data feed? We’d love to hear about it, let us know at media@climate-kic.org!

Please contact Michel Ramonet if you have any scientific questions about the data.


Climate-KIC is the European Union’s main climate innovation initiative. We are Europe’s largest public-private innovation partnership focused on finding new ways to bring down CO2 levels and stop further climate change, while creating growth and jobs in a new low-carbon economy.

With a headquarters in London, United Kingdom, we leverage Climate-KIC centres across Europe to educate the next generation of climate innovation leaders, support start-up companies and bring together partners on innovation projects.

If you can’t measure it, you can’t fix it! That’s why we also work with scientists to develop cost-effective technologies to measure greenhouse gases. We are one of the Knowledge and Innovation Communities (KICs) created the European Institute of Innovation and Technology (EIT), a body of the EU.

Go to the Climate-KIC website