Scientists are trained to be professional skeptics: to always judge the validity of a claim or finding on the basis of objective, empirical evidence. They are not cynics; they just ask themselves and each other a lot of questions. If they see a claim that a finding is true, they will ask: 'Why'' They may hypothesize that if that finding is true, then some related findings must also be true. If it's unclear whether one or more of those other findings is true, they will do more work to find out. Dogmatism is the opposite of skepticism. It is the proclivity to assert opinions as unequivocally true without taking account of contrary evidence or the contradictory findings. It is why public debate over scientific findings never seems to go away. An example of the difference is the reaction to the Intergovernmental Panel on Climate Change's finding in 1995 that 'evidence suggests a discernible human influence on global climate.' The IPCC's assessment reports involve hundreds of researchers from around the world who reviewed the global scientific understanding of the planet's changing climate....

The idea began in California's Sierra Nevada, a towering spine of rock and ice where rising temperatures and the decline of snowpack are transforming ecosystems, sometimes with catastrophic consequences for wildlife. The prairie-doglike Belding's ground squirrel (Urocitellus beldingi) had been struggling there as the mountain meadows it relies on dry out in years with less snowmelt and more unpredictable weather. At lower elevations, the foothill yellow-legged frog (Rana boylii) was also being hit hard by rising temperatures, because it needs cool, shaded streams to breed and survive. We were able to locate meadows that are less vulnerable to climate change, where the squirrels would have a better chance of thriving. We also identified streams that would stay cool for the frogs even as the climate heats up. Some are shaded by tree canopy. Others are in valleys with cool air or near deep lakes or springs. Identifying these pockets of resilient habitat ' a field of research that was inspired by our work with natural resource managers in the Sierra Nevada ' is now helping national parks and other public and private land managers to take action to protect these refugia from other threats, including fighting invasive species and pollution and connecting landscapes, giving threatened species their best chance for survival in a changing climate....

The latest United Nations Climate Change Conference (COP30) concluded in November without a roadmap to phase out fossil fuels and without significant progress in strengthening national pledges to reduce climate-altering greenhouse gas emissions. In aggregate, today's climate policies remain far too unambitious to meet the Paris Agreement's goal of capping global warming at 1.5 degrees Celsius, setting the world on course to experience more frequent and intense storms, flooding, droughts, wildfires, and other climate impacts. A global policy regime aligned with the 1.5 C target would almost certainly reduce the severity of those impacts. In the '2025 Global Change Outlook,' researchers at the MIT Center for Sustainability Science and Strategy (CS3) compare the consequences of these two approaches to climate policy through modeled projections of critical natural and societal systems under two scenarios. The Current Trends scenario represents the researchers' assessment of current measures for reducing greenhouse gas (GHG) emissions; the Accelerated Actions scenario is a credible pathway to stabilizing the climate at a global mean surface temperature of 1.5 C above preindustrial levels, in which countries impose more aggressive GHG emissions-reduction targets....

In a new study, our team of scientists investigated how ice melting in Antarctica affects global climate and sea level. We combined computer models of the Antarctic ice sheet, solid Earth and global climate, including atmospheric and oceanic processes, to explore the complex interactions that melting ice has with other parts of the Earth. Understanding what happens to Antarctica's ice matters, because it holds enough frozen water to raise average sea level by about 190 feet (58 meters). As the ice melts, it becomes an existential problem for people and ecosystems in island and coastal communities. The extent to which the Antarctic ice sheet melts will depend on how much the Earth warms. And that depends on future greenhouse gas emissions from sources including vehicles, power plants and industries. Studies suggest that much of the Antarctic ice sheet could survive if countries reduce their greenhouse gas emissions in line with the 2015 Paris Agreement goal to keep global warming to 1.5 degrees Celsius (2.7 Fahrenheit) compared to before the industrial era. However, if emissions continue rising and the atmosphere and oceans warm much more, that could cause substantial melting and much higher sea levels....