A new paper published in Philosophical Transactions of the Royal Society A, explains weaknesses in our understanding of climate change and how we can fix them. These issues mean predictions vary wildly about how quickly temperatures will rise. This has serious implications for long term political and economic planning. The papers lead author is Dr Nigel Fox of The National Physical Laboratory, The UK's National Measurement Institution.
The Earth's climate is undoubtedly changing, but how fast and what the implications will be are unclear. Our most reliable models rely on data acquired through a range of complex measurements. Most of the important measurements - such as ice cover, cloud cover, sea levels and temperature, chlorophyll (oceans and land) and the radiation balance (incoming to outgoing energy) – must be taken from space, and for constraining and testing the forecast models, made over long timescales. This presents two major problems.
Firstly, we have to detect small changes in the levels of radiation or reflection from a background fluctuating as a result of natural variability. This requires measurements to be made on decadal timescales – beyond the life of any one mission, and thus demands not only high accuracy but also high confidence that measurements will be made in a consistent manner.
Secondly, although the space industry adheres to high levels of quality assurance during manufacture, satellites, particularly optical usually lose their calibration during the launch, and this drifts further over time. Similar ground based instruments would be regularly calibrated traceable to a primary standard to ensure confidence in the measurements. This is much harder in space.
The result is varying model forecasts. Estimates of global temperature increases by 2100, range from ~2-10◦C. Which of these is correct is important for making major decisions about mitigating and adapting to climate change: for instance how quickly are we likely to see serious and life threatening droughts in which part of the world; or if and when do we need to spend enormous amounts of money on a new Thames barrier. The forecasted change by all the models is very similar for many decades only deviating significantly towards the latter half of this century.
Dr Nigel Fox, head of Earth Observation and Climate at NPL, says: "Nowhere are we measuring with uncertainties anywhere close to what we need to understand climate change and allow us to constrain and test the models. Our current best measurement capabilities would require >30 yrs before we have any possibility of identifying which model matches observations and is most likely to be correct in its forecast of consequential potentially devastating impacts. The uncertainties needed to reduce this are more challenging than anything else we have to deal with in any other industrial application, by close to an order of magnitude. It is the duty of the science community to reduce this unacceptably large uncertainty by finding and delivering the necessary information, with the highest possible confidence, in the shortest possible time."
The solution put forward by the paper is the TRUTHS (Traceable Radiometry Underpinning Terrestrial- and Helio- Studies) mission, a concept conceived and designed at NPL. This which would see a satellite launched into orbit with the ability to not only make very high accuracy measurements itself (a factor ten improvement) but also to calibrate and upgrade the performance of other Earth Observation (EO) satellites in space. In essence it becomes "NPL in Space".
The Earth's climate is undoubtedly changing, but how fast and what the implications will be are unclear. Our most reliable models rely on data acquired through a range of complex measurements. Most of the important measurements - such as ice cover, cloud cover, sea levels and temperature, chlorophyll (oceans and land) and the radiation balance (incoming to outgoing energy) – must be taken from space, and for constraining and testing the forecast models, made over long timescales. This presents two major problems.
Firstly, we have to detect small changes in the levels of radiation or reflection from a background fluctuating as a result of natural variability. This requires measurements to be made on decadal timescales – beyond the life of any one mission, and thus demands not only high accuracy but also high confidence that measurements will be made in a consistent manner.
Secondly, although the space industry adheres to high levels of quality assurance during manufacture, satellites, particularly optical usually lose their calibration during the launch, and this drifts further over time. Similar ground based instruments would be regularly calibrated traceable to a primary standard to ensure confidence in the measurements. This is much harder in space.
The result is varying model forecasts. Estimates of global temperature increases by 2100, range from ~2-10◦C. Which of these is correct is important for making major decisions about mitigating and adapting to climate change: for instance how quickly are we likely to see serious and life threatening droughts in which part of the world; or if and when do we need to spend enormous amounts of money on a new Thames barrier. The forecasted change by all the models is very similar for many decades only deviating significantly towards the latter half of this century.
Dr Nigel Fox, head of Earth Observation and Climate at NPL, says: "Nowhere are we measuring with uncertainties anywhere close to what we need to understand climate change and allow us to constrain and test the models. Our current best measurement capabilities would require >30 yrs before we have any possibility of identifying which model matches observations and is most likely to be correct in its forecast of consequential potentially devastating impacts. The uncertainties needed to reduce this are more challenging than anything else we have to deal with in any other industrial application, by close to an order of magnitude. It is the duty of the science community to reduce this unacceptably large uncertainty by finding and delivering the necessary information, with the highest possible confidence, in the shortest possible time."
The solution put forward by the paper is the TRUTHS (Traceable Radiometry Underpinning Terrestrial- and Helio- Studies) mission, a concept conceived and designed at NPL. This which would see a satellite launched into orbit with the ability to not only make very high accuracy measurements itself (a factor ten improvement) but also to calibrate and upgrade the performance of other Earth Observation (EO) satellites in space. In essence it becomes "NPL in Space".