Climate Scientists Release Draft of Special Report in Fear That Current U.S. Administration Will Bury It

August 8, 2017 – A climate science draft report by the U.S. Global Change Research Program was released to the public this week. A product of scientists from 13 different federal agencies, it was produced as the fourth part of an ongoing climate assessment mandated by Congress. The report serves as an authoritative assessment related to the science of climate change and its related risks with a focus on the United States in particular. It is not meant to provide strategies for mitigation or adaptation. Nor does it calculate the economic and social impact. It is a document devoid of policy but rich in evidence.

The agencies involved are the National Oceanic and Atmospheric Administration (NOAA), the Federal Science Steering Committee, NASA, the Department of Energy, the Environmental Protection Agency (EPA), and the Global Change Research Program of the federal government. Their findings are based on peer-reviewed research, observational data sets, modeling data sets, and other publicly available records. Only data and information that met the authors quality assurance guidelines are used in compiling the report. That means the information and data have to be transparent, traceable, objective, and secure.

The released draft is defined as a fifth version and final before the document is published. Why release it in this form? It appears the scientists who are the researchers and authors are concerned that the final version might never see the light of day because of the current climate science denial orientation of elected and appointed operatives in the Trump administration. So they have leaked it.

In the Executive Summary of the report, it references the last version published in May 2014 and states unequivocally that “stronger evidence has emerged for continuing, rapid, human-caused warming of the global atmosphere and ocean.” It goes on to cite the evidence: record-breaking warmth in three of the last four years since the last version was tabled, record declines in Arctic sea ice, increased ocean acidification and warming throughout the entire water column from the sea bed to the surface, and increasing frequency of severe weather events.

It notes that since 1986 average temperatures have risen faster than at any other time in the past 1,700 years, the period of time where the global distribution of surface temperatures can be reconstructed with a high degree of confidence.

It states that the human contribution to global mean temperature increases since 1951 amounts to between 0.6 and 0.8 Celsius (1.1 to 1.4 Fahrenheit) degrees while screening out the impacts of natural variability such the North Atlantic Oscillation, Northern Annular Mode, North Pacific Oscillation, Pacific North American Pattern which all impact the United States in particular, and global phenomena such as the El Nino, La Nina, and volcanic eruptions. The report also considers the documented expansion of the Earth’s tropical climate zone poleward by 110 to 320 kilometers (70 to 200 miles) from 1979 and 2009 in projecting future climate. The report declares with a high degree of confidence that human involvement is the prime causal agent, calculating the certainty between 92 and 123%.

Projections are Not What Climate Science Skeptics Want to Hear

The report projects with very high confidence that global climate will continue to change for the remainder of the century and beyond. It states that with significant reductions in greenhouse gas emissions (GHGs) the mean rise can be limited to 2 Celsius (3.6 Fahrenheit). It further states with high confidence that without major GHG reductions that mean global temperatures will increase by 5 Celsius (9 Fahrenheit) by the end of the century.

It states, that with significant reductions in greenhouse gas emissions (GHGs), the mean rise can be limited to 2 Celsius (3.6 Fahrenheit), the number the IPCC and COP21 climate agreement fixate on. But it forecasts, with high confidence, that without major GHG reductions mean global temperatures will increase by 5 Celsius (9 Fahrenheit) by the end of the century. And if GHGs were to remain at current levels the world would still warm another 0.6 Celsius (1.1 Fahrenheit) over the remainder of the century.

These are hard science numbers. The projections are based on calculating representative concentration pathways (RCPs), the radiative force of energy in watts per square meter from increases in GHGs. Different emission pathways project different results but they all are dependent on GHG concentrations of methane (CH4), carbon dioxide (CO2), nitrogen dioxide (NO2), water vapour and particulate matter (black carbon). And in all cases, the data points to more significant warming.

As for the United States in Particular

The report states that the average annual temperature over the contiguous states (the lower 48) has increased by 1.0 Celsius (1.8 Fahrenheit) from 1901 to 2016. The majority of that increase has occurred in the period between 1986 and 2016 when temperatures rose 0.7 Celsius (1.2 Fahrenheit). Its projections, stated with very high confidence, show that temperatures will rise a further 1.4 Celsius (2.5 Fahrenheit) for the next several decades under all emission scenarios described above with much larger rises projected late in the century (between 1.6 and 4.1 Celsius (2.8 to 7.3 Fahrenheit) in a lower emission scenario, and 3.2 to 6.6 Celsius (5.8 to 11.9 Fahrenheit) with higher emissions). Add in the urban heat island effect and we will see a further exaggeration in both day and nighttime temperatures. In the day by as much as 4.0 Celsius (7.2 Fahrenheit), and in evenings by as much as 2.5 Celsius (4.5 Fahrenheit).

Beyond temperature extremes, the United States will see changes in precipitation patterns. The report notes with high confidence that what is seen in the historical record since 1901, increasing precipitation events both in frequency and intensity, will continue. The same will be true for droughts and heat waves which in the historical record have reached record intensity in a number of regions in the United States over the past four decades. Winter and spring snow cover, snowstorm frequency, storm tracks, and tornado activity will be impacted. Soil moisture levels are expected to decline to put crops in peril. Forest fires are projected to increase in frequency and size. And tropical cyclones (hurricanes) are expected to increase in intensity both in the Atlantic and Pacific Oceans.

Oceans and Sea Level Rise

The report states that global mean sea level has risen between 16 and 21 centimeters (7 to 8 inches) since 1900. Just under half of that rise has occurred since 1993. At the same time, ocean heat content has increased overall at all depths with surface water warming by 0.7 Celsius (1.3 Fahrenheit) over the same period. If GHG emissions are not reduced the projections indicate average sea surface temperatures will rise by 2.7 Celsius (4.9 Fahrenheit) by the end of the century.

For the United States, in particular, coastal sea level rise is not just about a warming and expanding ocean or the melting of sea ice and polar ice sheets. U.S. coastal sea levels are also affected by ocean circulation and land subsidence. That means tidal flooding which has increased by 500 to 1,000% since the 1960s will continue to increase. This, when combined with increased tropical cyclones particularly along the Atlantic and Gulf of Mexico coastlines, will lead to flood risk amplification.

The changes to global ocean circulation, particularly the Atlantic Meridional Overturning Circulation (the Gulf Stream) is a wild card. The report states with low confidence that the circulation may weaken by between 12 and 54% by 2100. The problem in making such projections is the paucity of observational data. The Argo program may fill in some of these blanks for future reports.

Other issues within the report cover acidification resulting from the ocean being the largest carbon sink for CO2 on the planet. Projections see surface ocean acidity rising to unprecedented heights not seen in 66 million years. At the same time declining oxygen concentrations are expected by as much as 3.5% by century end as surface temperatures, rising sea levels, precipitation and wind pattern alterations, and ocean circulation all contribute causing oxygen dead zones such as the one that was recently described, as large as the state of New Jersey, off the Louisiana Gulf Coast.

As for Alaska – Ouch

The report notes that average surface air temperatures across Alaska have increased in the last 50 years at more than double the global average rate. The impact on permafrost melt and land ice loss is abundantly evident. Since 1984 Alaskan glaciers have continuously lost ice mass. And offshore, sea ice has decreased by 3.5 to4.1% per decade and has become thinner by between 1.3 and 2.1 meters (4 to 7 feet). Projections indicate sea ice loss will continue throughout the 21st century and that by the 2040s late summers will see an ice-free Arctic Ocean.

Unanticipated Changes

In other climate reports, they talk about tipping points. These are thresholds that when crossed lead to larger impacts. The report states that “unanticipated and difficult or impossible-to-manage changes in the climate system are possible throughout the next century as critical thresholds are crossed and/or multiple climate-related extreme events occur simultaneously.”

So that’s a quick overview of the findings. The full draft report has been made available by the New York Times should you choose to read it. Its release comes in the same week that the U.S. government, through the State Department, formally confirmed President Trump’s previous announcement that the U.S. was withdrawing from the Paris Climate Agreement.

 


Len Rosen lives in Toronto, Ontario, Canada. He is a researcher and writer who has a fascination with science and technology. He is married with a daughter who works in radio, and a miniature red poodle who is his daily companion on walks of discovery.
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