Reputable Sources

Not all sources of information are created equal. Go to scientific organizations for your science–not to entertainment media, popular news, blogs, radio, or op-ed articles. Every scientific organization in the world has come to the same general conclusions about human-caused climate change: the Earth is warming, it's us, we're sure enough to act, and it's urgent.

There is scientific consensus about this understanding:

There is a big difference between scientific consensus and political consensus. It takes a consensus of all the available evidence to reach scientific consensus.

The Fourth National Climate Assessment (v1): Causes

This report summarizes what NASA, NOAA, the EPA, DOD, DOE, and other major US scientific organizations understand about climate change and how confident they are in that understanding based on all the available evidence.

From the two-page Executive Summary Highlights:

"This assessment concludes, based on extensive evidence, that it is extremely likely that human activities, especially emissions of greenhouse gases, are the dominant cause of the observed warming since the mid-20th century. For the warming over the last century, there is no convincing alternative explanation supported by the extent of the observational evidence."

The term "extremely likely" indicates a 95-100% level of confidence.

The Fourth National Climate Assessment (v2): Impacts and Risks

The Overview provides a national summary and Chapter 18 is about impacts on the Northeast: From the Overview:

"Earth’s climate is now changing faster than at any point in the history of modern civilization, primarily as a result of human activities. The impacts of global climate change are already being felt in the United States and are projected to intensify in the future—but the severity of future impacts will depend largely on actions taken to reduce greenhouse gas emissions and to adapt to the changes that will occur. Americans increasingly recognize the risks climate change poses to their everyday lives and livelihoods and are beginning to respond (Figure 1.1). Water managers in the Colorado River Basin have mobilized users to conserve water in response to ongoing drought intensified by higher temperatures, and an extension program in Nebraska is helping ranchers reduce drought and heat risks to their operations. The state of Hawai‘i is developing management options to promote coral reef recovery from widespread bleaching events caused by warmer waters that threaten tourism, fisheries, and coastal protection from wind and waves. To address higher risks of flooding from heavy rainfall, local governments in southern Louisiana are pooling hazard reduction funds, and cities and states in the Northeast are investing in more resilient water, energy, and transportation infrastructure. In Alaska, a tribal health organization is developing adaptation strategies to address physical and mental health challenges driven by climate change and other environmental changes. As Midwestern farmers adopt new management strategies to reduce erosion and nutrient losses caused by heavier rains, forest managers in the Northwest are developing adaptation strategies in response to wildfire increases that affect human health, water resources, timber production, fish and wildlife, and recreation. After extensive hurricane damage fueled in part by a warmer atmosphere and warmer, higher seas, communities in Texas are considering ways to rebuild more resilient infrastructure. In the U.S. Caribbean, governments are developing new frameworks for storm recovery based on lessons learned from the 2017 hurricane season.

Climate-related risks will continue to grow without additional action. Decisions made today determine risk exposure for current and future generations and will either broaden or limit options to reduce the negative consequences of climate change. While Americans are responding in ways that can bolster resilience and improve livelihoods, neither global efforts to mitigate the causes of climate change nor regional efforts to adapt to the impacts currently approach the scales needed to avoid substantial damages to the U.S. economy, environment, and human health and well-being over the coming decades."

The Carbon Cycle: short- versus long-term carbon (ie. biomass versus fossil fuels)

Why is burning wood different than burning coal? Because when a tree falls, all or most of all of the carbon in it will end up back in the air in the span of a human life-time and another tree can grow in it's place, removing the same amount of carbon from the air in that same timeframe. It's a balanced, sustainable cycle (land-use changes not withstanding).

Fossil fuels consist of carbon that hasn't been in the air for hundreds of millions of years, and when it was in the air, the climate was something for which dinosaurs, not humans, were well adapted. Our infrastructure, food and water systems, bodies, and nature around us are not suited to withstand the higher global temperatures of that previous age.

What's the rush?

At our current rate of carbon emissions we will exceed the limit that gives us a 50:50 chance of holding global warming below 1.5˚C in several years. Scientists call this our remaining carbon budget. The IPCC's Special Report on 1.5˚C of Global Warming shows the emissions reduction path we need to get on now to hold warming to 1.5˚C (pages 6 and 13): net-zero emissions by 2050 and a CO2 level at 350 ppm or less before 2100.

It also compares the risks, impacts, and damages of warming by 1.5˚C and by 2˚C. NASA summarized the stark differences. That difference makes it clear we must do everything possible to avoid 2˚C of warming.

The UN's Emissions Gap Report demonstrates the greatly increased difficulty of achieving the safer target if we delay for just five more years.

Pick an ecosystem, any ecosystem

Ecosystems around the world are already being impacted by human-caused climate change, from coral reefs to Arctic tundra. This is a major driver of the Earth's sixth mass-extinction.

For example, we've lost 50% of the world's tropical coral reefs in the last 30 years from 1˚C of global warming since 1900. Most of that warming occurred in the last four decades.

The differences in damage to life on Earth between 1.5˚C and 2˚C of global warming is enormous. According to the IPCC SR15 report (above), we'll lose 70-90% of the world's coral reefs from 1.5˚C warming and 98-100% from 2˚C warming. The difference is about 20 years of emissions at the current rate.

1.5˚C of warming is virtually impossible to avoid, but if we act immediately and effectively it is technically possible for us to avoid 2˚C of warming. Our emissions choices over the next decade will determine our future.

See also: The Sixth Extinction by Elizabeth Kolbert.

A YouTube Playlist of science, economics, policy, and climate communication videos

The Earth's climate is changing, and we know why through science with a high level of confidence. The political climate must change so we can address the causes. There are bipartisan ways to make that happen that will also help make our Democracy stronger: YouTube PlayList.