Monthly CO2 emissions projections from 2015-2025: modified SSP2-4.5 to account for COVID-19 impacts on sector activity

Note that the data and normalisation process used in the aviation data is subtly updated since the version 4 found in related databases, hence that is referred to as v4.5. It still does not cover the whole month of July, due to publication date. The whole dataset is now considered version 4.5.4 as it features more years and differently cropped timeframes to versions 4.5.0-2 (these now extend to 2050) and fixes a bug associated with 4.5.3. The input data is still consistent with versions 4.5.0 and 4.0.