# InVEST Coastal Blue Carbon mode

**URL:** <https://community.naturalcapitalalliance.org/t/invest-coastal-blue-carbon-mode/949>\
**Category:** Software Support\
**Tags:** blue-carbon\
**Created:** [April 22, 2020, 2:14pm UTC](https://community.naturalcapitalalliance.org/t/invest-coastal-blue-carbon-mode/949 "2020-04-22T14:14:55Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Nimal](https://avatars.discourse-cdn.com/v4/letter/n/6a8cbe/32.png) [@Nimal](https://community.naturalcapitalalliance.org/u/Nimal)\
**Post date:** [April 22, 2020, 2:14pm UTC](https://community.naturalcapitalalliance.org/t/invest-coastal-blue-carbon-mode/949/1 "2020-04-22T14:14:56Z")

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Hello

We used the InVEST Coastal Blue Carbon model for one of our undergraduate research projects in 2018, and we found the following issue. Therefore, I shall very much thankful if you could solve that and make me aware?

\*\* Our Issue:\*\* The lowest NPV values are for the lowest discount rate. Higher discount rates give higher NPV values. Please explain this.

Hope, you all are safe at the current situation!

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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:** [April 22, 2020, 6:50pm UTC](https://community.naturalcapitalalliance.org/t/invest-coastal-blue-carbon-mode/949/2 "2020-04-22T18:50:10Z")

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This could be consistent with intended model output, depending on the distribution of net gains and losses across the landscape. If there is only sequestration over the landscape, then total NPV (across the landscape) should be lower with higher discount rates, all else equal. If there is only net emission, then total NPV should be higher with higher discount rates, all else equal. If there is both emission and sequestration, then the relationship is ambiguous and depends on both the values and their timing.

A small [spreadsheet example](https://www.dropbox.com/s/1289a0dxbz8ekxg/Book1.xlsx?dl=0) should hopefully help clarify this.

Please do reach out though if I’ve misinterpreted your issue or you believe there to be a problem with the model.

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**Author:** ![Nimal](https://avatars.discourse-cdn.com/v4/letter/n/6a8cbe/32.png) [@Nimal](https://community.naturalcapitalalliance.org/u/Nimal)\
**Post date:** [April 23, 2020, 1:23am UTC](https://community.naturalcapitalalliance.org/t/invest-coastal-blue-carbon-mode/949/3 "2020-04-23T01:23:58Z")

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Thanks for the prompt reply!