diff --git a/.readthedocs.yaml b/.readthedocs.yaml
index aa1d52e446..fe6eb48d85 100644
--- a/.readthedocs.yaml
+++ b/.readthedocs.yaml
@@ -12,12 +12,14 @@ python:
    install:
    - requirements: docs/sphinx/requirements.txt
 
+conda:
+   environment: docs/environment.yml # needed until ubuntu ships doxygen >= 1.9.8
+
 build:
    os: ubuntu-22.04
    tools:
-      python: "3.10"
+      python: "mambaforge-22.9" # needed until ubuntu ships doxygen >= 1.9.8
    apt_packages:
-     - "doxygen"
      - "gfortran" # For pre-processing fortran sources
      - "graphviz" # For dot graphs in doxygen
    jobs:
diff --git a/docs/environment.yml b/docs/environment.yml
new file mode 100644
index 0000000000..a3dbd898d7
--- /dev/null
+++ b/docs/environment.yml
@@ -0,0 +1,10 @@
+name: RTD
+channels:
+  - conda-forge
+  - defaults
+dependencies:
+  - python=3.10
+  - pip
+  - doxygen=1.9.8
+  - pip:
+    - -r ./sphinx/requirements.txt