Carbon optimization Report in Azure is showing emissions for a subscription without any actual ressources

Question

The only reason that subscription exists is, that we need it to buy Visual Studio licenses. And those do not produce CO2 emission. So is the Carbon Optimization Report wrong?

Answer 1

It’s actually normal for Azure’s Carbon Optimization Report to show emissions even if a subscription has no active resources. In most cases this happens because the report is still looking at all the subscriptions you have access to unless you manually filter it, or because there were resources or background services deployed in that subscription at some point within the last 12 months. Azure keeps carbon data for a full year, so even brief usage—like spinning up a test resource, enabling a preview feature, or having hidden system‑created items such as Log Analytics workspaces—can still show emissions long after the resources are gone. The best approach is to go into the Carbon Optimization blade, open the subscription filter, uncheck every subscription except your Visual Studio license subscription, and apply the filter to confirm the data is isolated to just that subscription. Also check “All resources” for that subscription or run az resource list to make sure nothing (including hidden or automatically created resources) still exists. If you still see emissions, look at the date range—old activity will remain visible until it ages out of the 12‑month window. If everything is filtered correctly, no resources exist, and you’re still seeing emissions, then it’s almost certainly due to historic or briefly‑provisioned activity still being included in the retained carbon data rather than an error in the report.

Answer 2

Hello @Ahmer Khan,

Most often this happens because the Carbon optimization blade shows data for whatever subscriptions you’ve selected (by default it may include all subscriptions you have access to), or because you had some test resources in that sub at some point in the last 12 months. Carbon optimization data is retained for a year, so any resource you spun up—even briefly—will still surface emissions until that rolling window passes.

 

Here’s what you can check:

1. Make sure you’ve filtered down to only your Visual Studio subscription      - In the Azure portal, go to Carbon optimization      - Open the Subscriptions filter and uncheck everything except the one used for VS licenses      - Hit Apply—you should now see emissions just for that one sub  

 

2. Confirm there really are zero resources in that subscription      - In the portal, browse to All resources in that sub (or run az resource list --subscription <your-sub-id>)      - If you see any resources (even hidden ones like Log Analytics workspaces created by preview features), they’ll contribute to emissions  

 

3. If you still see non-zero values:      - Check the date range. By default you see the last 12 months—so old usage will still appear until it ages out      - Verify whether any background services ran (for example brief provisioning operations) that might have generated usage  

 

If after filtering to only that sub and confirming zero resources you still see emissions, let me know: • which months are showing emissions   • whether you’ve ever deployed/tested anything in that sub   • screenshots of the Subscriptions filter and the emissions chart  

 

That info will help pin down whether it’s a data-retention artifact or something else.

 

Reference docs: 

• View and analyze emissions data: https://learn.microsoft.com/azure/carbon-optimization/view-emissions
• Troubleshooting Carbon optimization: https://learn.microsoft.com/azure/carbon-optimization/troubleshooting 
• What is Carbon optimization: https://learn.microsoft.com/azure/carbon-optimization/overview