According to reports, the northern hemisphere is relatively densely populated, and human activities such as the burning of fossil fuels continue to drive up carbon emissions, so the carbon dioxide concentration in the atmosphere of the northern hemisphere reached the benchmark level of 400PPM in 2013. In contrast, the southern hemisphere has less human activity, while Antarctica is sparsely populated, but even so, the carbon dioxide concentration in Antarctica reached the benchmark value of 400PPM in June 2017. Based on the above information, is the following inference correct? ['The impact of human activities on the earth has reached the polar regions.', 'Increased carbon dioxide concentration has a profound impact on Antarctica landforms.', 'Carbon dioxide concentration in Antarctica will not drop below 400PPM.', 'Carbon dioxide concentrations in the Arctic far exceeded those in the Antarctic 4,5 years ago.']