Query: Evidence is building that net cloud feedback is likely positive and unlikely to be strongly negative.

Relevant passages:
Evidence-based medicine <=SEP=> Evidence-based medicine ( EBM ) is an approach to medical practice intended to optimize decision-making by emphasizing the use of evidence from well-designed and well-conducted research . Although all medicine based on science has some degree of empirical support , EBM goes further , classifying evidence by its epistemologic strength and requiring that only the strongest types ( coming from meta-analyses , systematic reviews , and randomized controlled trials ) can yield strong recommendations ; weaker types ( such as from case-control studies ) can yield only weak recommendations . The term was originally used to describe an approach to teaching the practice of medicine and improving decisions by individual physicians about individual patients . Use of the term rapidly expanded to include a previously described approach that emphasized the use of evidence in the design of guidelines and policies that apply to groups of patients and populations ( `` evidence-based practice policies '' ) . It has subsequently spread to describe an approach to decision-making that is used at virtually every level of health care as well as other fields ( evidence-based practice ) .   Whether applied to medical education , decisions about individuals , guidelines and policies applied to populations , or administration of health services in general , evidence-based medicine advocates that to the greatest extent possible , decisions and policies should be based on evidence , not just the beliefs of practitioners , experts , or administrators . It thus tries to assure that a clinician 's opinion , which may be limited by knowledge gaps or biases , is supplemented with all available knowledge from the scientific literature so that best practice can be determined and applied . It promotes the use of formal , explicit methods to analyze evidence and makes it available to decision makers . It promotes programs to teach the methods to medical students , practitioners , and policy makers .

Evidence <=SEP=> Evidence , broadly construed , is anything presented in support of an assertion . This support may be strong or weak . The strongest type of evidence is that which provides direct proof of the truth of an assertion . At the other extreme is evidence that is merely consistent with an assertion but does not rule out other , contradictory assertions , as in circumstantial evidence .   In law , rules of evidence govern the types of evidence that are admissible in a legal proceeding . Types of legal evidence include testimony , documentary evidence , and physical evidence . The parts of a legal case which are not in controversy are known , in general , as the `` facts of the case . '' Beyond any facts that are undisputed , a judge or jury is usually tasked with being a trier of fact for the other issues of a case . Evidence and rules are used to decide questions of fact that are disputed , some of which may be determined by the legal burden of proof relevant to the case . Evidence in certain cases ( e.g. capital crimes ) must be more compelling than in other situations ( e.g. minor civil disputes ) , which drastically affects the quality and quantity of evidence necessary to decide a case .   Scientific evidence consists of observations and experimental results that serve to support , refute , or modify a scientific hypothesis or theory , when collected and interpreted in accordance with the scientific method .   In philosophy , the study of evidence is closely tied to epistemology , which considers the nature of knowledge and how it can be acquired .

Global warming controversy <=SEP=> The global warming controversy concerns the public debate over whether global warming is occurring , how much has occurred in modern times , what has caused it , what its effects will be , whether any action should be taken to curb it , and if so what that action should be . In the scientific literature , there is a strong consensus that global surface temperatures have increased in recent decades and that the trend is caused by human-induced emissions of greenhouse gases . No scientific body of national or international standing disagrees with this view , though a few organizations with members in extractive industries hold non-committal positions . Disputes over the key scientific facts of global warming are more prevalent in the media than in the scientific literature , where such issues are treated as resolved , and such disputes are more prevalent in the United States than globally .   Political and popular debate concerning the existence and cause of climate change includes the reasons for the increase seen in the instrumental temperature record , whether the warming trend exceeds normal climatic variations , and whether human activities have contributed significantly to it . Scientists have resolved these questions decisively in favour of the view that the current warming trend exists and is ongoing , that human activity is the cause , and that it is without precedent in at least 2000 years . Public disputes that also reflect scientific debate include estimates of how responsive the climate system might be to any given level of greenhouse gases ( climate sensitivity ) , how global climate change will play out at local and regional scales , and what the consequences of global warming will be .   Global warming remains an issue of widespread political debate , often split along party political lines , especially in the United States . Many of the issues that are settled within the scientific community , such as human responsibility for global warming , remain the subject of politically or economically motivated attempts to downplay , dismiss or deny them -- an ideological phenomenon categorised by academics and scientists as climate change denial . The sources of funding for those involved with climate science -- both supporting and opposing mainstream scientific positions -- have been questioned by both sides . There are debates about the best policy responses to the science , their cost-effectiveness and their urgency . Climate scientists , especially in the United States , have reported official and oil-industry pressure to censor or suppress their work and hide scientific data , with directives not to discuss the subject in public communications . Legal cases regarding global warming , its effects , and measures to reduce it have reached American courts . The fossil fuels lobby has been identified as overtly or covertly supporting efforts to undermine or discredit the scientific consensus on global warming .