Claim: CO2 increase is natural, not human-caused

Relevance (1 = gold evidence, 0 = mined hard negative): 1
Passage: While CO 2 absorption and release is always happening as a result of natural processes, the recent rise in CO 2 levels in the atmosphere is known to be mainly due to human (anthropogenic) activity.

Relevance (1 = gold evidence, 0 = mined hard negative): 1
Passage: Human activities have caused CO 2 to increase above levels not seen in hundreds of thousands of years.

Relevance (1 = gold evidence, 0 = mined hard negative): 1
Passage: Human activity since the Industrial Revolution has increased the amount of greenhouse gases in the atmosphere, leading to increased radiative forcing from CO2, methane, tropospheric ozone, CFCs, and nitrous oxide.

Relevance (1 = gold evidence, 0 = mined hard negative): 1
Passage: It is likely that anthropogenic (i.e., human-induced) warming, such as that due to elevated greenhouse gas levels, has had a discernible influence on many physical and biological systems.

Relevance (1 = gold evidence, 0 = mined hard negative): 1
Passage: In 2007 climate scientists of the IPCC concluded that there was at least a 90% probability that atmospheric increase in CO2 was human-induced, mostly as a result of fossil fuel emissions but, to a lesser extent from changes in land use.

Relevance (1 = gold evidence, 0 = mined hard negative): 0
Passage: While ‘climate change’ can be due to natural forces or human activity, there is now substantial evidence to indicate that human activity – and specifically increased greenhouse gas (GHGs) emissions – is a key factor in the pace and extent of global temperature increases.

Relevance (1 = gold evidence, 0 = mined hard negative): 0
Passage: Rennie 2009: "Claim 1: Anthropogenic CO2 can't be changing climate, because CO2 is only a trace gas in the atmosphere and the amount produced by humans is dwarfed by the amount from volcanoes and other natural sources.

Relevance (1 = gold evidence, 0 = mined hard negative): 0
Passage: The reason for this is that human activities are adding CO2 to the atmosphere faster than natural processes can remove it (see carbon dioxide in Earth's atmosphere for a complete explanation).

Relevance (1 = gold evidence, 0 = mined hard negative): 0
Passage: Anthropogenic climate change is caused by human activity, as opposed to changes in climate that may have resulted as part of Earth's natural processes.

Relevance (1 = gold evidence, 0 = mined hard negative): 0
Passage: US National Academy of Sciences: "In the judgment of most climate scientists, Earth's warming in recent decades has been caused primarily by human activities that have increased the amount of greenhouse gases in the atmosphere.

Relevance (1 = gold evidence, 0 = mined hard negative): 0
Passage: Attributing detected temperature changes and extreme events to human-caused increases in greenhouse gases requires scientists to rule out known internal climate variability and natural external forcings.

Relevance (1 = gold evidence, 0 = mined hard negative): 0
Passage: Human activities are now causing atmospheric concentrations of greenhouse gases—including carbon dioxide, methane, tropospheric ozone, and nitrous oxide—to rise well above pre-industrial levels ... Increases in greenhouse gases are causing temperatures to rise ...

Relevance (1 = gold evidence, 0 = mined hard negative): 0
Passage: Cumulative anthropogenic (i.e., human-emitted) emissions of CO 2 from fossil fuel use are a major cause of global warming, and give some indication of which countries have contributed most to human-induced climate change.