Update README.md

Author: alanedelman

README.md

@@ -124,7 +124,7 @@ Use your Project 2a, incorporating suggestions, to make an amazing Pluto noteboo
 |11|W|10/9| Student Projects |||
 |  |M|10/14| Indigenous People's Day |||
 | 12  | W   | 10/16  | Edelman             | Economic Model of Climate                            | [Slides](slides_old/ClimateMARGO.pdf)                                                                                                             | [Economic Model](https://computationalthinking.mit.edu/Fall23/climate_science/inverse_climate_model/), [Optimization with JUMP](https://computationalthinking.mit.edu/Fall23/climate_science/optimization_with_JuMP/)                                                                                                                                                    |
-| 13 | M  | 10/21  | Ferrari           | Intro to Climate    | 
+| 13 | M  | 10/21  | Ferrari           | Intro to Climate    | [Slides](notebooks/13_ferari_lecture1.pdf) |
 |14| W| 10/23 | Ferrari | Energy Balance Models ||
 |15|M|10/28| Souza | Climate Emulators||
 |16|W|10/30| Edelman | Snowball Earth |[Snowball Earth and hysteresis](https://computationalthinking.mit.edu/Fall23/climate_science/climate2_snowball_earth/)  |