The greenhouse effect is a simple chemical reality: carbon compounds in the atmosphere trap heat, like a greenhouse roof. At the optimum level, atmospheric greenhouse gases make life as we know it possible; outside the optimum range, many stable geophysical processes become unstable, and civilization becomes harder to establish and secure.
For most of the history of the human species, atmospheric concentrations of CO2 were between 180 parts per million (ppm) and 280 ppm. There has never been a time in the history of the human species on Earth when atmospheric CO2 rose above 300 ppm, until the last few decades of industrialization. Ongoing and escalating greenhouse gas emissions have now pushed atmospheric CO2 levels to more than 400 ppm, and as high as 411 ppm.

From 280 ppm (the historic periodic high) to 411 ppm is an increase of 46%. Oxygen levels at the top of Mont Blanc (16,000 feet above sea level) are roughly 46% lower than at sea level. Here is a description of what happens to a human body introduced too rapidly to the low oxygen levels at 16,000 feet of altitude:
Your blood oxygen saturation will have dropped to 79 percent and you will be seriously disabled. You will be euphoric, belligerent, disoriented or perhaps all three. You will be irrational, unreliable and dangerous. If you are alone, your chances of survival are decreasing rapidly.
46% is an enormous change in atmospheric conditions.
The historic change in greenhouse gas concentrations is driving a steady warming of temperatures in the ocean, over land, and in particular across the more sensitive Polar Regions. Fresh water stored in glaciers is disappearing across the world. At least 1.5 billion people depend on water stored in the disappearing glaciers of the Himalayan and Hindu Kush mountain ranges.
Risk vs. Resilience
The assumptions that allow civilization to exist — that there are institutions, laws, accountability, that paper money has value, that violence is forbidden — start to come apart when water is unattainable. Choices become stark: change the rules regarding who owns what, or migrate.
Because institutions also tend to come apart when there is no way to get water, the vulnerable people left behind tend to migrate — first to nearby cities, then to larger cities, then across borders. Climate refugees are already flooding into cities like Dhaka, Bangladesh. When they find too little opportunity there, they go on to elsewhere, crossing borders.
Climate change is an existential threat to ecosystems, to specific human populations, and even to organized civilization as we know it. The migration crisis we have experienced in the last 10 years (a larger number of people displaced internationally than at any time since World War II) is just the beginning.
Asylum laws and refugee receiving policies are nowhere near generous enough to cope with the coming wave of climate migrants. Tougher restrictions are not a serious option, because they will only lead to an expansion of human suffering and further destabilization of the kind that drives migration.
Some argue we should just “be practical” and aim to build appropriate coastal infrastructure.
- As a reference, Miami Beach is trying to do this; its ongoing round of infrastructure improvements to deal with sea level rise will cost $500 million. 92,300 people live there.
- Scale that cost to all of the people who live at or near sea level (600 million people), and the cost to counter sea-level rise quickly reaches into the trillions of dollars. That is just one system impact of unchecked climate disruption.
- We also need to adapt our entire food system, our heavy industry, energy production and transportation, and standards for small and large-scale construction, everywhere.
- We must accelerate adaptation. We should start investing intelligently now; we cannot treat the hardening of infrastructure as the most affordable way forward, if we do nothing else to stop climate disruption.
Insurers are increasingly concerned that vital segments of their industry may become mathematically obsolete. If payouts from extreme events continue to hit record levels, there won’t be enough money in circulation to make commercial insurance profitable. Efforts to achieve a sustainable insurance future are gathering momentum, along with a call to investors to report climate risk and develop fully climate-smart portfolios.
The message: climate change is an existential threat, and we must organize deliberately, imaginatively, and aggressively, to reduce the threat to life and treasure. The science and the numbers say we can “solve” climate change, if we change how we get energy, invest in resilience at all levels, and expand natural carbon-sinking capacity.
Looking to the Future
There are high-value cost-effective simple policy changes that can drive investment in this climate-smart future.
- Changing property value assessments for farm land to account for soil carbon richness, without raising taxes on that land, can create a vast economy of scale across multiple sectors, moving finance and investment to climate-smart food, water, and commodities, and greatly reducing agricultural pollution.
- An upstream fee on carbon-emitting fuels (at the mine, well or port of entry), with all revenues returned to households, can efficiently correct the market’s failure to price climate-forcing emissions, while creating millions of jobs, raising incomes, and growing the economy. The bipartisan Energy Innovation and Carbon Dividend Act — H.R. 763 — is currently before 3 committees in the House of Representatives.
- Redirection of subsidies that currently incentivize pollution can create vast new opportunities to invest in and profit from clean alternative technologies, while driving innovation and new efficiencies in existing industries to compete for dollars that demand low emissions.
- Renewable portfolio standards provide market clarity for energy producers and consumers, allowing for cost-effective performance-based incentives that can eliminate municipal emissions, then scale to eliminate emissions within cities, and then expand to state and region-wide clean energy markets.
- Green bonds provide a powerful incentive for dedicated, localized, job-creating investment in climate-smart infrastructure, energy, transport, and industry, all of which have public-health and quality-of-life benefits at the local leve
It is also important to recognize that all of these administratively simple, straightforward, catalytic approaches also interact with each other in a way that enhances overall climate resilience and sustainable development. All of these strategies create clear investable incentives for responsible enterprise and healthy market economies (where investment for private gain aligns with the routine generation of generalized public good).
Cynical Naysaying is Surrender
Climate change is an existential threat. Naysaying the possibility of responsible, immediate, economically virtuous climate action — or arguing it will “cost too much” — would be surrender, and a betrayal of the public trust.
The Green New Deal is an outline of principles and goals that tracks with real problems facing our nation. To argue it is “unrealistic” is to say we should not solve these problems. If doing all of this in one comprehensive national plan is impractical, politically, then critics should outline their solutions to the problems the Green New Deal seeks to address, and seek to make those solutions real, without further delay.
Climate change is the first true planetary system challenge to human civilization. It requires us to achieve a level of innovation and collaboration unprecedented in human history. The complex work of meeting that challenge is not beyond our collective imagination, political will, or culture of open enterprise.
In fact, the United States is as prepared to meet this challenge as any society could be. We need to get to work.