The environmental effects of large igneous provinces (LIPs) on global climate changes and mass extinction events have became one of the most important topics in geosciences. Most researchers believe that greenhouse and toxic gases, sulfur aerosols and other volatiles released during eruption of flood basalt in LIPs are main reasons for driving global climate changes and mass extinctions. However, recent results suggest that contact metamorphism during emplacement of large volumes of mafic sill swarms as main component of LIPs has significant environmental effects. Emplacement of large volumes of mafic sill swarms into black shales, coal, evaporate and carbonate will release huge volumes of greenhouse and toxic gases and other volatiles, which may trigger and drive the environmental perturbations and mass extinctions. The ~1.32 Ga Yanliao (northern Hebei—western Liaoning) LIP in the northern North China Craton (NCC) consists mainly of large volumes of diabase sill swarms and has an areal extent over 1.2×105km2. Most of the diabase sills emplaced into the black shales of the Xiamaling Formation with total organic carbon (TOC) values of 0.6%~20% and average TOC values of ~6.0%; other emplaced into the dolostone and dolomitic limestone of the Wumishan and Gaoyuzhuang formations. Field investigations show that both sides of the black shales were affected by emplacement of sills and the thicknesses of the hornfelsing and decarbonation zones could be 5 to 10 meters. TOC analytical results of the black shales near or far from the contact zones suggest that emplacement of the ~1.32 Ga diabase sills into the black shales in the NCC could have generated ~1,098 Gton CO2. If the diabase sills emplaced into the carbonates of Wumishan and Gaoyuzhuang formations in the northern NCC and the ~1.32 Ga Derim Derim diabase sills emplaced into the black shales of the Velkerri Formation in the McArthur Basin in the North Australian Craton were considered together, the greenhouse and toxic gases generated by emplacement of ~1.32 Ga diabase sills could be more huge than present estimation. Release of CO2 and other gases during emplacement of the large volumes of Yanliao diabase sills in the northern NCC and the Derim Derim diabase sills in the North Australian Craton may have significant environmental effects on atmosphere and oceans. Since the ~1.32 Ga depositions in the NCC and North Australian Craton are absent, geological records for environmental effects such as negative carbon isotope excursion, element or other isotopic anomalies due to emplacement of diabase sill swarms may exist in other cratons such as Siberia, Baltica, etc., and more researches are needed to test this hypothesis.