Climate Science

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 difference between scientific consensus and political consensus.  It takes a consensus of all the available evidence plus a consilience of  experts in multiple fields of  science to achieve scientific consensus.

The Fifth National Climate Assessment

This is the US Government’s preeminent report on climate change impacts, risks, and responses. It is a congressionally mandated interagency effort that provides the scientific foundation to support informed decision-making across the United States.

From the report:

The Fourth National Climate Assessment (v1): Causes

This is the previous version (2017-2018) of the US's National Climate Assessment.

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 based on all the evidence.

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

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

What's the rush?

At the current rate of GHG emissions from human activities, we only have several years before we will exceed the carbon budget that offers a 50:50 chance of holding global warming to 1.5˚C this century.  The IPCC's Special Report on 1.5˚C of Global Warming shows potential emissions reduction paths we could follow to hold warming to 1.5˚C (pages 6 and 13):  net-zero emissions by 2050 and negative emissions for the second half of the century to achieve an atmospheric CO2 concentration of 350 ppm or less before 2100.

This report also compares the differences in risks, impacts, and damages of global warming by 1.5˚C and by 2˚C.  NASA summarized these differences in a summary report.  The differences make it clear we share a responsibility to avoid 2˚C of warming.

The UN's Emissions Gap Report demonstrates the greatly increased difficulty of holding warming below 1.5˚ C if we delay for even just five more years.

Are we sure it's us?

Yes, we are sure.  The climate has always changed, and we know why through science.  The IPCC's Fifth Assessment Report (Chapter 8) reviews all the natural and man-made climate forces since 1750 (warming and cooling).  The two main warming forces are the man-made increase in CO2 (gray) and CH4 (methane, the main contributor in the well-mixed greenhouse gases represented in light green) in Figure 8.18 (page 699).

The IPCC Sixth Assessment Report: IPCC AR6 WG1

greenhouse gas warming partly masked by aerosol cooling."

The 2021 New Hampshire Climate Assessment

This report was supported by funding from the New Hampshire Department of Environmental Services and produced by NH State Climatologist M.D. Lemcke-Stampone, C.P. Wake, and E.A. Burakowski, from The Sustainability Institute, University of New Hampshire

A 200-year History of Climate Science

Where We Are

Our Energy Future

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.

Biodiversity Loss

Ecosystems around the world are 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 are 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.

On Biodiversity loss:  "These culprits are, in descending order: (1) changes in land and sea use; (2) direct exploitation of organisms; (3) climate change". "climate change... impacts expected to increase... in some cases surpassing the impact of land and sea use change." - IPBES Report

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.

Why CFD 2020