Class News
Tom Barnard ’64 on climate projections to mid-century
USA Climate Conditions in 2050
by Tom Barnard ‘64
August 29, 2020
The purpose of this essay is to describe, based on science, what the climate will feel like at mid-century in the United States. The science of global climate change is settled. Burning fossil fuels emits carbon dioxide (CO2) into the atmosphere which persists, accumulates, and increases the global temperature. The temperature increase is proportional to the total amount of CO2 released over time. The details are complicated but the essential phenomenon is simple. Atmospheric CO2 blankets and warms the earth through the action of the sun and the greenhouse effect.
Before getting into predictions, let us briefly review the history of international agreements on climate change. Starting in 1995, annual conferences called Conferences of Parties (COP) have taken place under United Nations auspices with the goal of reducing global warming. Currently 200 countries participate. COP3 in 1997 drafted the Kyoto Protocol, which specified commitments for countries to reduce CO2 emissions. The governments of many countries approved the agreement but the United States did not. COP21 in 2015 resulted in the Paris Agreement with the world-wide goal of limiting warming to 1.5 °C by year 2100 and specific CO2 emission limits by country. President Obama approved the agreement, but Congress never ratified it. President Trump withdrew USA commitment to the agreement.
Economic and physical realities make reaching and implementing international agreements to reduce CO2 emissions difficult. Per capita GDP tends to be proportional to per capita energy consumption. Limiting global temperature rise to a specific target requires limiting all future CO2 emissions aggregated over all countries. Less wealthy countries want a greater per capita share of the future CO2 budget so their standard of living can catch up. Wealthy countries want to continue growing their per capita GDP. Also, poorer countries want wealthier countries to help subsidize their conversion to renewable energy. The only solution is for renewable (and other non-fossil-fuel) energy to be cheaper than fossil-fuel energy. Substantial investments will be required, which imply economic opportunities as well as costs.
Predictions about future climate conditions must consider various time delays regarding CO2 emissions and temperature. As a thought experiment, if we stopped all CO2 emissions tomorrow, the global climate temperature would continue rising for at least 20 more years. This fact is due to the thermal inertia of physical matter, especially the oceans. In other words, the full global warming effect of CO2 emitted today will take at least 20 years to occur.
Another delay is the time it takes people to decide to replace energy generated by fossil fuels with renewable energy such as wind or direct solar power. Also, infrastructure which consumes fossil fuels, such as electric-power plants, have economic lives lasting 40 years or more. And it takes time to install the new infrastructure. Such considerations add decades of delays to actual reductions of CO2 emissions.
Partisan party politics are outside the scope of this essay. However, they too can impact the timing of fossil-fuel CO2 emission changes.
The International Panel on Climate Change (IPCC) was formed by the United Nations in 1988 to document and publish the most carefully verified, internationally sourced, scientific information about climate change. To predict the average global climate temperature in 2050, we shall use their quantitative mathematical models and realistic assumptions about CO2 emissions. Our assumed CO2 emissions are an average of the current actual level and its growth rate, combined with moderate reductions in the growth rate going forward. These assumptions are realistic in view of historical data, time delay considerations, and previously unfulfilled international commitments for CO2 reductions.
The predicted average global climate temperature in 2050, thus calculated, is +2.2°C (4°F) relative to pre-industrial times. For comparison, the global climate temperature change today is about +1°C. What will the USA climate feel like in 2050 compared to today? For that we look to various peer-reviewed scientific reports, and reports about reports, which utilize mathematical models to simulate specific climate and weather conditions based on recent data and the predicted future global temperature.
The amount of Arctic sea ice has a major impact on world weather systems. Due to global warming, the area of Arctic sea ice at the end of summer is shrinking rapidly. The northwest passage sought by early European explorers is becoming a reality. By 2050 the North Pole most probably will be free of ice by the end of each summer. Before global warming there was a persistent, cold, high-pressure system over the North Pole, which stabilized the jet stream and North American weather patterns. As temperature increases, the north-polar high will diminish and continental weather will become more variable and intense. There will be more frequent and longer droughts, more extreme temperatures both high and low, more intense rainfall events, and more river flooding than typical of the 20th century. The breadbasket regions of our midwest will be subjected to higher summer temperatures and longer droughts, reducing grain yields and thus food availability both domestically and internationally.
Winter snow in the Sierra Nevada mountains plays an essential role in the availability of fresh water for human consumption and agricultural irrigation in northern California and its Central Valley. Normally, snow accumulates in the winter and melts in the summer, releasing water gradually into rivers for local use. Global warming already is causing premature snow melting which results in excessive flow in the winter and insufficient flow in the summer. The consequence is inadequate water in summertime for households and agriculture. About 25% of USA food produce comes from the California Central Valley, which will be reduced by the summer water deficit as 2050 approaches.
Wildfires in California are increasing in frequency and intensity due to droughts caused by global warming. Recently there have been many record-breaking fires causing deaths and property destruction. Examples include the Ferguson fire in 2018 (Yosemite and nearby), the SNU and LNU Complex fires in 2020 (Napa, Sonoma, Santa Clara, etc.) and the Camp fire in 2018 (Butte county). The prospect of increasing numbers of wildfires due to global warming is terrorizing many California residents.
Climate models indicate that tropical hurricanes will increase in intensity, size, and frequency due to global warming. Higher ocean-water temperatures release greater concentrations of water vapor into the atmosphere, charging it with vast amounts of energy which, under the right conditions, can become focused into tropical storms. Think of the devastation caused by Hurricanes Katrina (2013, Cat 3, New Orleans), Andrew (1992, Cat 5, Florida), Michael (2018, Cat 5, Florida), Sandy (2012, Cat 1, New York), Hugo (1989, Cat 4, Charleston SC), Maria (2017, Cat 4, Puerto Rico and USVI), Harvey (2017, Cat 4, Houston TX) and many others. Damage is caused by high winds, flooding due to storm surges, and extreme rainfall. NOAA is considering the definition of Category 6 to characterize future, higher-intensity hurricanes. Mindful of gradually rising sea levels and the threat of tropical storms, coastal residents from New England to Texas are concerned every hurricane season. Twenty years ago, there were more than four major insurance companies writing homeowner policies along the Georgia coast. Now there is only one. As 2050 approaches and the global temperature rises, hurricane damage will become more severe.
Climate models for 2050 indicate that increasing droughts and excessively high temperatures will cause food and water scarcity in many areas around the world. Starvation causes desperate people to flee unviable locations. Already Europe is struggling with how to handle climate refugees from Syria, the Middle East, and Africa. When subsistence farmers in Central America suffer crop failure caused by drought, they often desperately try to reach North America. The USA is currently experiencing national political repercussions from these disasters. More severe climate conditions will make the pressures worse. Presently there are political trends around the world towards isolationism and autocracy.
Considering the effects of global warming, what will America feel like in 2050? Assuming no unforeseen catastrophic events, our country probably will still be intact. Although our major coastal cities will be habitable, they will be subjected to frequent flooding. Climate change will have eroded the quality of life for average citizens. There will be more exposure to adverse weather events such as droughts, floods, and cyclonic storms. Food availability will be reduced. We probably will have diminished control over our physical and geopolitical environments. Resources will be consumed by recovery from weather disasters rather than by improvements in infrastructure. Our economic and political systems will be under increasing stress.
The big question in 2050 will be what about the next 50 years? If mankind finally has started decreasing the amount of CO2 emitted into the atmosphere, we can be hopeful that global warming may be reduced and that civilization, as we know it, may survive into the next century.
Tom was a physics major at Yale and went on to earn his PhD in physics at NYU followed by an MBA from the University of Connecticut. He spent his career at Perkin-Elmer Corporation, working in the fields of aerospace and scientific instruments. He retired as a Perkin-Elmer vice president.
See a video presentation by Tom on global climate change.