iht answers added

EXERCISES/teachers_info.md

@@ -21,6 +21,21 @@ print(tau)
 tau = 2*(0.0132-0.0105)/(0.006-0.001)
 print(tau)
 
+### Reading the emission data
+
+# reading csv file 
+import pandas as pd
+
+df = pd.read_csv("https://ourworldindata.org/grapher/annual-co2-emissions-per-country.csv?v=1&csvType=full&useColumnShortNames=false", storage_options = {'User-Agent': 'Our World In Data data fetch/1.0'})
+df = df.set_index(['Entity'])
+df = df.loc['World']
+df = df.set_index(['Year'])
+df['kton C/yr'] = df['Annual CO₂ emissions']/44.*12./1e3 
+df['PgC/yr'] = df['Annual CO₂ emissions']/44.*12./1e9
+
+recent = df[df.index > 1999]
+recent['PgC/yr'].plot(color='red',marker='o',lw=2)
+
 ### Plotting the student-made distribution of sink strengths:
 
 import numpy as np