Global warming

Even with aggressive international and whole-of government action to mitigate future climate change, many effects to the physical environment are now unavoidable and will continue to shape our security environment.

Department of Defense Climate Risk Analysis, October 2021

Our world has warmed, on average, 1.2°C (2.2°F) from pre-industrial levels. The earth's energy imbalance shows we have locked in more than 1.5°C of warming and must act now to avoid a catastrophic future. Our oceans have absorbed 90% or more of the excess heat and are responsible for some of the atmospheric CO² reduction, resulting in acidification. The average temperature over land is significantly higher than over oceans, but isn't the same increase everywhere across the world. For example, the arctic is warming three times faster than other parts of the earth, threatening the polar ice caps and could bring an additional 0.4°C of warming if we see an ice-free arctic during the summer months.

Limiting warming to 2.0°C requires dramatic decreases in greenhouse gas emissions within the next few years. It may even be impossible to restrict heating to 2.0°C. Any temperature overshoot due to greenhouse gases requires extracting massive amounts of CO² from the atmosphere or another form of geoengineering. The technologies to do this are expensive, not ready at scale, have unanswered questions on side effects, and require large amounts of energy.

We are incapable of this level of greenhouse gas reduction today. Proposed "net-zero" programs focus on offsetting through carbon credits: paying for some amount of carbon removal, thereby artificially reducing one's emissions. Most of these use natural processes like tree growth, which we desperately need apart from carbon removal. Another touted approach is to capture generated emissions at oil, coal, and gas power stations. However, this technology is costly, reduces energy production, is unavailable at scale, and its strategic effectiveness is questionable in light of the recent supreme court ruling. Discussing net-zero or negative-emissions technologies without first stressing the importance of reducing emissions only encourages reliance on technological salvation. We do not have the tech today, making it a very poor bet for the survival of our species. Long term capture and storage of greenhouse gases has always been meant as a stop-gap if we were unable to meet necessary emissions reductions.

Our world relies on fossil fuels for 65% of our electricity production and 85% for all energy (electricity, transportation, and heating). Energy demand continues to increase and is predicted to outpace efficiency gains and the availability of new renewable energy sources. The U.S. Energy Information Administration estimates around 50% growth in energy use by 2050, supported by increased use of fossil fuels. We are not curbing our energy appetite nor do we have the technology to make fossil fuels "clean" — even ignoring ecological disasters from pollutants, mining byproducts, and pipeline spills.

EIA projects that renewable energy will be the fastest-growing source of energy through 2050, but petroleum and liquid fuels will remain the most-consumed source of energy.

U.S. Energy Information Administration, March 3rd 2022

World governments pledge commitments (called NDCs) to monitor and limit greenhouse gases. If met, these promises may hold the average warming of our planet to 2.3°C. But governments don't have a strong track record of keeping promises, and climate is no exception. Current policies indicate we could expect a 2.7°C world. However, present inaction keeps us on a trajectory of 3.4°C by the end of the century — and still rising. Study after study has revealed flaws in emissions data, accountability, and failure to adhere to these promises.

There is another solution: begin using less energy, and soon. This isn't a call to change your thermostat but to pressure politicians and other leaders to implement meaningful changes addressing the growing climate crisis. Over 80% of greenhouse gas emissions come from fossil fuel usage in the electricity, agriculture, manufacturing, and transportation industries and that is where our focus has to be. It must be real pressure to counteract the fossil fuel industry's money and lobbying. One study found the fossil fuel industry receives $11 million every minute. That is our tax money spent to bandaid health and ecological crises created by for-profit companies. Another shows $1.8 trillion in subsidies goes toward "the annihailation of wildlife and a rise in global heating". A strong first step in this direction is to implement a carbon fee & dividend, charging a fee when fossil fuels are extracted from the earth and distributing the proceeds to the general public. As the world's richest 10% are responsible for about half of the world's emissions, this helps the people most impacted by climate change but have the least capability to adapt. Fee & dividend along with ending subsidies exposes the true cost of fossil fuels and creates a monetary, market-driven incentive to decrease their use. There is an act before congress, the Energy Innovation and Carbon Dividend Act, to lay the foundation for such a program, but it is at strong risk of not passing.

We must also change our relationship with land use and its associated biodiversity loss before we cause a 6th mass extinction. Much of our industrial and development activities continue to threaten and destroy ecosystems, directly through deforestation and overfishing or indirectly by raising temperatures across the planet. Our world is intricately connected, and we are quickly approaching irreversible ecological tipping points.

Climate scientists are clear: we must act now to avoid worsening effects of climate change

Greenhouse gas emissions must peak soon and begin decreasing dramatically. Yet global emissions are projected to grow through 2050.

Untapped fossil fuels must stay in the ground. Still, our governments continue approving new fossil fuel extraction projects.

Transformations to address climate change must include youth, labor, Indigenous Peoples, and local communities. Instead, our leaders press forward with investment policies benefiting the already rich while ignoring the very real consequences forced upon global populations.

To correct temperature overshoot, at least 170 gigatons of CO² must be removed from our atmosphere by 2050, an average of 6 gigatons per year — more than the United States' annual emissions. Today we can only remove 0.8% of that amount annually.