Archiving our climate system space-based climate research with ESA?s climate change initiative...

Archiving our climate system space-based climate research with ESA?s climate change initiative r

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With the end of the climate talks in Paris in December 2015, comes new momentum to engage the world — not just to reflect on past errors, but moreover to act on the growing concern with bolder solutions. Meanwhile, climate change is the reality we face today, and not just a problem for generations to come. It is clear that policymakers need to step up a gear and proactively make decisions that will help the world adapt to rising air temperatures and their knock-on effects. These decisions need to be grounded in science. To draw up a comprehensive strategy for tackling the consequences of a changing climate, we need to first decipher climate patterns and trends.
Climate is not weather. To describe climate is to define the variables that characterize the Earth’s climate system. These variables are known as Essential Climate Variables (ECVs). The concept of ECVs was developed by the Global Climate Observing System (GCOS) in support of the United Nations Framework Convention on Climate Change (UNFCCC). To understand climate variability long time series of ECV data are needed. Field measurements have illustrated historic climate change — the iconic diagram of rising CO2 levels measured at Mauna Loa Observatory in Hawaii springs to mind. They are the foundations that led to our awareness of a warming planet. Field campaigns continue to provide invaluable climate records, yet they are spatially limited. With satellite records dating back to the late 1970s, we have arrived at the moment in time when climate, with the aid of this 30 plus year archive, can be observed globally from space. It seems fair to say that a significant amount of climate science today is based on a satellite-era understanding of the coupled interactions between the atmosphere, ocean and the land. 

Clearly, it is the space agencies that need to rise to the occasion, and so they are. What has become known as the international architecture for climate monitoring from space, developed by international coordination mechanisms including the Committee on Earth Observation Satellites (CEOS), has brought the space agencies together and pointed them in the direction of research harmonization, explicitly stating the importance of open data-sharing policies. Apart from coordinating amongst each other, international programs to observe, calculate and archive ECV datasets have been initiated. The largest coordinated program doing this is the European Space Agency’s (ESA) Climate Change Initiative (CCI). The CCI is ESA’s effort to liaise with and fund scientists across member states, helping them delve deep into the satellite archives to produce these much needed ECV data records. 

In 2017, the CCI will come to an end. Eight years of hard work and €95 million investment will ultimately culminate in an operational ECV data record, ready to be used by climate services. To sum up the achievements so far, let us return to the objectives drawn up at the start of the program. The CCI set out to provide ECV data records, focusing on the needs of the climate modelling community. Spatially distributed numerical models rely on satellite data for parametrization and validation. Pivotal to underpinning the dynamics of our climate system in models is to provide standardized, consistent data with appropriate uncertainty estimates. These ECV data records need to be built by stable, transparent processing algorithms with the final products scrutinized by the user communities. With these goals in mind, the ESA CCI presents improvements to current algorithm retrievals and to standardization of global multi-mission ECV products — achievements that detail once more the triumph of strong international cooperation

Fit for purpose?

The range of CCI ECV products is discrete but certainly not insignificant, covering each domain: atmosphere, ocean and land. A total of 13 ECVs are considered, the selection of which was made according to the requirements that the derived data sets would need to be scientifically relevant, technically feasible and cost-effective — the demand for climate data records may be high, but without manageable monetary resources, the all-necessary continuity in producing and archiving these ECV data sets is at risk. Under the CCI umbrella, 14 projects were set up — one for each chosen ECV and a standalone project, the Climate Modelling User Group, set up as a consortium of climate modellers to assess, validate and provide feedback on each dataset. This involvement of the main climate modelling research centres across Europe, and their independent assessment of the CCI products ensures these ECV records are exactly what the doctor ordered. Of necessity is the indisputable easy and free access to these data. With this in mind, the ESA CCI Open Data Portal, currently under construction, will be the point of reference for obtaining the full suite of CCI ECV records. Experience suggests that access to data must be as straightforward as possible, or else the products will not be used to their full potential. Much thought has gone into crafting such a Web-interface, and its arrival is much anticipated.
The success-story of ESA CCI will be measurable by the statistics of downloaded data and published research. In part, this is already being done by the consortium of scientists working on the ESA CCI program, but others will come once the portal opens. Then, hopefully, the impact of these studies will be far more impressive on the political landscape and decision-making processes.

Key to operational climate service

ESA CCI is certainly a step in the right direction, but we have not completely established the magic formula for providing an operational climate service. There are a substantial number of ECVs that, despite being within the scope of ESA CCI, are currently not considered and would, therefore, call for new R&D. However, we also need to continue to monitor and deliver the ECV datasets, which we so meticulously produced over the past few years. Climate research needs the continuity of long-term observations. The dilemma of choosing between continuity and R&D is solved, keeping in line with the spirit of collaboration. The former is ensured by passing the ECV archives on to operational entities outside the ESA CCI program, such as the European Commission’s Copernicus Climate Service, the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT) Satellite Application Facilities (SAFs) and other active services on the national level, while the latter will be undertaken by ESA CCI and subsequent programs. These R&D efforts are therefore a key functional cog in the mechanism that is climate research, helping to revolutionize the way we model climate.

Smart outreach for a smart generation

Bringing our research closer to the public is paramount in a society that craves information in the palm of its hands. As a publicly funded organization, ESA is committed to produce valuable and free outreach resources. Under the CCI program an iPad app, known as the ESA CCI Visualization Tool, has been developed. Its purpose is to communicate why we need satellites for climate and how the chosen CCI ECVs narrate the story of a changing climate. An inbuilt data viewer visualizes the CCI data sets, and patterns of change seen from the satellites are made visible to the eye. At the tap of a touchscreen, a time series of satellite-derived sea surface temperature measurements illustrate changes through time, and the layman too is able to spot known climate phenomena, such as El Niño. Furthermore, the effects of global warming trends, for instance on the cryosphere, are also made more apparent to the public as they can view time series of Arctic sea ice concentrations. But this app is about more than just viewing the output of the ESA CCI program. It is a tool to raise awareness of our planet’s changing climate system. Striking animations help paint the picture. For instance, one movie zooms into Antarctica, showing the marine-based West Antarctic Ice Sheet (WAIS) and explaining how Pine Island Glacier, which drains a large part of the WAIS, is retreating and how we can measure this withdrawal using radar interferometry. We see how the margin of the glacier’s grounded ice has retreated inland by about 40 km, now grounded several hundreds of meters deeper than the subsea ridge it had been anchored on in the 1990s — what remains is a long, fragile tongue hovering and flexing in a warming ocean.

Meanwhile, the Twitter-sphere is full of opportunities for outreach. Eager to share our news, views and links to interesting research, the ESA climate office has long been on twitter (@esaclimate). The advantages are clear; “It’s great that it’s an interactive environment, so people can ask questions,” says Cat Downy, a scientist with the International Geosphere-Biosphere Program (IGBP) working as an ESA liaison officer. “It reaches different audiences — scientists and the general public.” This is not a new concept. In the last few years it has become common practice for scientists to share their thoughts and research on Twitter. It is almost an absolute necessity for developing a complete online profile. The digital age demands scientists to be concise and to the point. It is precisely this skill — to communicate science in a maximum of 140 characters — that allows ESA to reach beyond the confines of its known scientific community, to send out the message of why we need #spaceforclimate, and interact with those interested in learning more on this topic. 

In the wake of COP21

Keeping the public informed about our programs is an important aspect of our job. ESA’s presence at COP21 marked such an opportunity — to share with the world the reasons we need satellites for climate monitoring. The agreement that was reached demands the development of new methodologies for assessing historical carbon sources and sinks, but it also reiterates the need for climate observations. “In order to do that you need information from satellites,” says Pascal Lecomte at the European Space Agency’s Climate Office.

The Paris agreement calls for “strengthening scientific knowledge on climate, including research, [and] systematic observation of the climate system”. Not only is this a justification for ESA CCI, and any follow-up programs, but it also points out that decision makers rely on state-of-the-art scientific consultation; that there is always room for improving our observations and determining new metrics for measuring climate change and that research and development are equally important in order to establish an operational climate service compared to just maintaining a climate data archive. As we move into the future, ESA will not only have to establish a new climate monitoring program, but it will also have to work towards advancing current algorithms, to consider what new satellite sensors are needed and how the newly derived data are to be made compatible with the current standards or vice versa. 
Undoubtedly, despite ESA CCI coming to a close in 2017, we have not yet reached the end of the road. There still remains much to do. As we require ever more information on the state of our changing planet, the international space agencies will have to work closely together for a more effective and complete global climate observing program that will lay down the foundations for a strategy on climate adaptation and mitigation.