Claim: "The killer proof that CO2 does not drive climate is to be found during the Ordovician- Silurian and the Jurassic-Cretaceous periods when CO2 levels were greater than 4000 ppmv (parts per million by volume) and about 2000 ppmv respectively.

Relevance (1 = gold evidence, 0 = mined hard negative): 1
Passage: The Devonian (/dɪˈvoʊn.i.ən, də-, dɛ-/ dih-VOH-nee-ən, də-, deh-) is a geologic period and system of the Paleozoic, spanning 60 million years from the end of the Silurian, 419.2 million years ago (Mya), to the beginning of the Carboniferous, 358.9 Mya.

Relevance (1 = gold evidence, 0 = mined hard negative): 1
Passage: The Jurassic (/dʒʊˈræs.ɪk/ juu-RASS-ik; from the Jura Mountains) is a geologic period and system that spanned 56 million years from the end of the Triassic Period 201.3 million years ago (Mya) to the beginning of the Cretaceous Period 145 Mya.

Relevance (1 = gold evidence, 0 = mined hard negative): 1
Passage: The Ordovician spans 41.6 million years from the end of the Cambrian Period 485.4 million years ago (Mya) to the start of the Silurian Period 443.8 Mya.

Relevance (1 = gold evidence, 0 = mined hard negative): 1
Passage: The Silurian (/sɪˈljʊər.i.ən, saɪ-/ sih-LYOOR-ee-ən, sy-) is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at 443.8 million years ago (Mya), to the beginning of the Devonian Period, 419.2 Mya.

Relevance (1 = gold evidence, 0 = mined hard negative): 1
Passage: The Triassic (/traɪˈæs.ɪk/ try-ASS-ik) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.9 million years ago (Mya), to the beginning of the Jurassic Period 201.3 Mya.

Relevance (1 = gold evidence, 0 = mined hard negative): 0
Passage: In the early and middle Ordovician, temperatures were mild, but at the beginning of the Late Ordovician, from 460 to 450 Ma, volcanoes along the margin of the Iapetus Ocean spewed massive amounts of carbon dioxide, a greenhouse gas, into the atmosphere, turning the planet into a hothouse.

Relevance (1 = gold evidence, 0 = mined hard negative): 0
Passage: Reconstructed temperature records for the last 420 million years indicate that atmospheric CO 2 concentrations peaked at ~2000 ppm during the Devonian (∼400 Myrs ago) period, and again in the Triassic (220–200 Myrs ago) period.

Relevance (1 = gold evidence, 0 = mined hard negative): 0
Passage: Carbon dioxide concentrations dropped from 4,000 parts per million during the Cambrian periodabout 500 million years ago to as low as 180 parts per million during the Quaternary glaciation of the last two million years.

Relevance (1 = gold evidence, 0 = mined hard negative): 0
Passage: (BBC) 4 April A new, detailed record of past climate change has shown compelling evidence that the last ice age was ended by a rise in temperature driven by an increase in atmospheric carbon dioxide.

Relevance (1 = gold evidence, 0 = mined hard negative): 0
Passage: Atmospheric CO2 has risen over the last 150 years to current levels of over 390 ppmv, from the 180 – 300 ppmv of the prior 800 thousand years This rise in temperature has reduced the Arctic ice cap to 1,100,000 sq mi (2,800,000 km2),[citation needed] smaller than ever recorded.

Relevance (1 = gold evidence, 0 = mined hard negative): 0
Passage: Keeling’s Tellus article of 1960 presented the first monthly CO 2 records from Mauna Loa and Antarctica (1957 to 1960), finding a “distinct seasonal cycle…and possibly, a worldwide rise in CO2 from year to year.” By the 1970s, it was well established that the increase of atmospheric carbon dioxide was ongoing and due to anthropogenic emissions.

Relevance (1 = gold evidence, 0 = mined hard negative): 0
Passage: CO 2 currently forms about 410 parts per million (ppm) of earth's atmosphere, compared to about 280 ppm in pre-industrial times, and billions of metric tons of CO 2 are emitted annually by burning of fossil fuels.

Relevance (1 = gold evidence, 0 = mined hard negative): 0
Passage: Some climate change denial groups say that because CO 2 is only a trace gas in the atmosphere (roughly 400ppm, or 0.04%, 4 parts per 10,000) it can only have a minor effect on the climate.