Climate change is very much related to an energy disturbance. Over the last decades, human activities have significantly impacted our climate, mainly trough emission of greenhouse gases and aerosols, causing global warming and forcing a net flux imbalance of 0.5 – 1 W m-2 at the “ Top Of the Atmosphere ” (TOA). Quantifying how much extra heat related to the Earth’s energy imbalance has been generated by human activities, and how it affects our climate system is one of the key challenges faced by the climate research community.
The issue of the energy budget closure, taking into account the strong interplay between the Earth’s sea-level and energy cycles, has now become one of the hot topics in climate science, regarding the issue of an apparent “ plateau ” in global surface temperature evolution over approximately the last 15 years. During this period, the global Earth surface temperature has increased more slowly than during the previous decades, while the greenhouse gas emissions (now at about 400 ppm concentration) have accelerated. Moreover, land ice melt and sea level have continued to rise steadily. The current Working Group is also focusing on the following questions:
Where the extra heat building up in the system is going ?
How do Earth’s energy imbalance and ocean heating rate change ?
Developing the knowledge, and observational capability, necessary to track the energy flows through the climate system is therefore critical to better understand the relationships between climate forcing, response, variability and future changes. The current observing systems are not complete. For example, there is no absolute measurement of the net TOA radiation imbalance or no measurement of the deep ocean heat content below 1500 – 2000 m depth. In addition, observational uncertainties are still too large to precisely analyze the energy flows, given transitions in instrumentation data and data sampling. Hence, there is a critical need to combine different independent measurement approaches based on remote sensing and in situ measurements.
In this context, this initiative proposes to investigate the global Earth’s energy and sea level budgets by using and confronting different and independent measurement approaches of the energy fluxes and sea-level rise to advance our understanding of the budgets. This activity brings a new integrated perspective on uncertainties in, and consistencies across, both the energy-sea-level budgets focusing on a “golden period”, thereby complementing previous studies. It will also focus on observing systems, and in particular the space missions, needed to track energy flows in the Earth system. This Working Group will also discuss and analyze the processes recently involves in the literature to explain the apparent “ plateau ” in the increase of global mean Earth temperature.
Last update: April 7, 2016