Question: what is the pre-industrial level of co2 on earth
[{'answer': '280 ppm', 'provenance': [{'wikipedia_id': '11251601', 'title': "Carbon dioxide in Earth's atmosphere", 'start_paragraph_id': 2, 'start_character': 568, 'end_paragraph_id': 2, 'end_character': 575, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '11251601', 'title': "Carbon dioxide in Earth's atmosphere", 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 1108, 'bleu_score': 0.554992853691013, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 12646717364864542622}, 'section': 'Section::::Abstract.'}]}]