# Net Present Value of Sequestration in blue carbon model

**URL:** <https://community.naturalcapitalalliance.org/t/net-present-value-of-sequestration-in-blue-carbon-model/1193>\
**Category:** Software Support\
**Tags:** blue-carbon\
**Created:** [July 27, 2020, 6:20am UTC](https://community.naturalcapitalalliance.org/t/net-present-value-of-sequestration-in-blue-carbon-model/1193 "2020-07-27T06:20:52Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Selina](https://avatars.discourse-cdn.com/v4/letter/s/7ea924/32.png) [@Selina](https://community.naturalcapitalalliance.org/u/Selina)\
**Post date:** [July 27, 2020, 6:20am UTC](https://community.naturalcapitalalliance.org/t/net-present-value-of-sequestration-in-blue-carbon-model/1193/1 "2020-07-27T06:20:52Z")

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Hi，  
In the blue carbon model,If I enter the layer years 1990,1995,2000,2005. . . . . According to the formula in the documentation, the 1995 carbon value is calculated from the 1990-1995 net sequestration, and the 2000 carbon value is calculated from the 1995-2000 net sequestration. . . . .  
So I want to know how the carbon value of the base year(1990) in the layer output from the model is calculated?

And I have another question, can the value of blue carbon only be calculated for sequestered carbon? Can I use this software to calculate the blue carbon value of the total carbon stock? How am I supposed to do that?  
Thank you

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**Author:** ![rmgriffin](https://yyz1.discourse-cdn.com/flex031/user_avatar/community.naturalcapitalalliance.org/rmgriffin/32/23_2.png) [@rmgriffin](https://community.naturalcapitalalliance.org/u/rmgriffin)\
**Post date:** [July 27, 2020, 7:03pm UTC](https://community.naturalcapitalalliance.org/t/net-present-value-of-sequestration-in-blue-carbon-model/1193/2 "2020-07-27T19:03:43Z")

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The model only values changes in carbon storage (emission/sequestration) over time. This is due to: 1) the way social cost of carbon methods and carbon markets value carbon; 2) estimates of the value of non-marginal changes to carbon storage generally become more implausible as they get bigger, as with all ecosystem service values ([Bockstael et al., 2000](https://dx.doi.org/10.1021/es990673l))

If you insist on valuing the total carbon stock, I believe the model can accommodate if you simulate future landscapes as having no carbon storage potential.