Do we really need billion of Euro worth equipments (Satellite, Radar, etc.) to estimate biomass production, NDVI by plants or atms. complex processes?

My simple answer would be that the analysis of observations from such plateforms (satellite, radar etc.) is the basis on which our understanding of the atmosphere, oceans, ecosystems, etc. is formed. Observations are also use to validate any empirical or numerical models that we may develop. So such investments are the basis of scientific investigations and are therefore required to achieve a more advanced understanding of our environment and the complex mechanisms which drive its evolution.

Uma S Bhatt

It is critical that we look at the components of the earth system on multiple spatial scales. The satellites are the only way to view the large-scale hemispheric or global picture. But ground-level biomass measurements are also important as are the intermediate-scale biomass measurements. It is only when we understand what is going on at multiple scales will we start to understand how the system works. No one component is more important than the other and need to be viewed together to gain a comprehensive picture.

Benjamin Warr

It's a drop in the ocean in terms of expenditure compared to the budgets of the military and communications satellites, and it is coming from sources that do not take money away from other environmental budgets.

Mark R Drinkwater

Deforestation is critical to mankind, and recent efforts such as by the international space agencies are attempts to get to grips with the serious consequences. The global economic cost of the climate change impacts (e.g. from greenhouse gas emissions) of rapid deforestation could rise to around US$1tn a year by 2100. Meanwhile, the total cost of forest loss could be as high as 12 trillion US dollars in net present value terms (Eliasch Review, 2010). New mechanisms like REDD+ are currently being put in place to protect the forests, in particular in tropical regions and developing countries. The amount of money that needs to be transferred from developed to developing countries is largely accepted as being in excess of 20 billion US dollars annually (EC Communication on Deforestation, October 2007). Forest monitoring from space plays a key role in the implementation of REDD+. The European Space Agency's (ESA's) candidate Earth Explorer mission Biomass (including P-band radar), for example, is designed to quantify the standing stocks in forest biomass, and in particular to calculate the rate of change in tropical biomass. Such a satellite mission is the only way to obtain a uniform global view. The cost of such a mission is far eclipsed by the annual cost and consequences of inactivity.

http://www.official-documents.gov.uk/document/other/9780108507632/9780108507632.pdf

Benjamin Warr

Hmm, Mark, in the end I don't think the presence of the satellite will have any major effect on reducing deforestation in the developing world, or to speeden up REDD+ implementation. From my experience here in Zambia, deforestation results because (a) most people really really want to cut the forest down (as it is full of snakes - is the most common reason given) (b) government really is not that concerned and would gladly sacrifice a whole load of forest for a bit of growth to ensure they get re-elected (c) we have had adequate imagery for the past 30 years and that did not save Borneo's forests or large tracts of the Amazon (d) by the time the govt. agencies have understood REDD there won't be much forest left. No, the satellites are a useful tool, but alone will achieve nothing. Too much focus on the technology as a solution will simply distract from getting on witht he job of enforcing roadblocks, getting government monitors out in the field. However, as I say the total expenditure on environmental satellites is still a drop in the ocean compared to other forms of satellite, there is little budgetary overlap, so go for it too. Can only help in the long-run.

Mihai A. Tanase

To this topic I would add that without investment in research and people capable of understanding and using the vast amount of data that satellites are able to collect, those billions of dollars invested in satellite systems would be grossly underused.

Also, the space agencies should change data distribution policies so free of cost access to data become a standard (i.e., Landsat, MODIS and the future Sentinel 1 apparently). Only this way people will start understanding the huge potential of the frequent monitoring from space and using the data to the extent on their potential.

Finally, we need not only one mission here one mission there, we need continuity ...meaning similar sensors with similar acquisition plans being launched (i.e., Landsat and to a lesser extent ALOS PALSAR). What is the point of having a radar that acquires one polarization today, full-pol tomorrow and only two-pol the day after tomorrow and all these at different incidence angles, looking direction and time of year. Such changes will make the joint use of all those sensors much more difficult.