How big of a challenge is climate change and should we really care about it?

Climate change has been a topic of discussion in many media outlets and there have been numerous useful resources (as well as a lot of false claims) for such. I have been studying climate change and have been following ideas and breakthroughs for tackling it, and I thought it is worth sharing a brief overview of evidences and scientific facts about the topic, hoping to raise awareness and have a tiny little positive impact on those who are interested but not necessarily fully aware of the topic. In this article, I will focus on the following questions:

• Problem Statement (what is causing climate change?)
• What are the impacts of climate change?
• How certain are we about the causes and impacts?
• How hard is it to solve the climate change problem?
• How can we tackle climate change?

1. Problem statement (what is causing climate change?)

The problem of climate change roots down to energy demand and consumption. Our main sources of energy are fossil fuels (coal, oil, gas), all of which generate greenhouse gases (GHGs) when burned. Carbon (/CO2, the primary constituent of GHGs in the Earth’s atmosphere) has always been continuously exchanged between the atmosphere, oceans, and biosphere through the Earth’s Carbon Cycle (ref 1), as shown below.

Normally (in pre-industrial era), the CO2 emission and exchange rates were relatively stable and they balanced each other, which led to a stable concentration of CO2 in the atmosphere (200-300ppm). Notably, human activities and burning fossil fuels have significantly disrupted the carbon cycle, causing the CO2 levels to reach unprecedented levels never experienced on Earth during the past ~1 million years (exceeding 418ppm in 2020, according to NOAA)!

The Earth’s land and ocean surfaces continuously radiate thermal infrared energy (heat) that is received from the Sun. Greenhouse gases (including the CO2) absorb and radiate that heat, and gradually release it over time, just like bricks in a fireplace after the fire is out. Increases in GHGs have been trapping additional heat, which has raised the Earth’s average temperature (ref 2).

2. What are the impacts of climate change?

The risks of climate change are very large and global warming has already had dire consequences. The impacts of climate change are not ubiquitous in all locations, and the risks vary regionally. Nonetheless, we are all affected, no matter where in the world we live. Overall, here are a number of climate change impacts that have been experienced in the past few decades and will be exacerbated in the coming decades:

• More frequent and more severe extreme events (ref 3)
• Loss of large volume of Antarctic ice and protracted duration of low ice extent in the Arctic (ref 4)
• Sea level rise and higher risk of coastal flooding (ref 5)
• Extended duration and severity of wildfire season (ref 6,7)
• Expanding territory and spread of mosquitoes (ref 8)
• Ocean acidification and bleaching coral reefs (ref 9)
• Impaired public health and accelerated spread of infectious disease (ref 10)
• Reduced crop yield (ref 11)

 There is evidence that global warming is making storms more intense, floods more frequent, and heatwaves more severe in various locations around the globe. However, what we have seen so far is really the tip of an iceberg. Climate change is an accumulative problem, and each emission adds an additional increment of warming. Even if we stop emissions today, the earth does not start cooling for centuries, but we have prevented things from getting worse.

3. How certain are we about the causes and impacts?

A series of experiments conducted in 1856 revealed that altering the proportion of CO2 in the atmosphere would cause global warming. Since then, the relationship between GHGs and the earth’s climate has become a principle of modern meteorology. A short news clip from a New Zealand paper published in 1912 is an example that made the connection between burning fossil fuels and climate change.

The causes and effects of global warming have been demonstrated since 1988, when Dr. James Hansen from NASA made a landmark testimony before the U.S. Senate and stated that “the greenhouse effect has been detected (in the atmosphere), and it is changing our climate now”.

We had a very accurate prediction of CO2 concentration from about 30 years ago, when a group of scientists predicted the IS92a emissions scenario, which unfolded to be quite accurate. Additionally, the computer simulations and climate models from even 50 years ago correctly predicted global warming intensity and patterns (refs 12,13). Thus, scientists have warned about climate change causes and impacts for decades.

4. How hard is it to solve the climate change problem?

Humans are generally good at solving immediate problems that can benefit the people who solve it, like a global pandemic. Unfortunately, climate change is a problem that manifests through decades and centuries (so, the impacts or benefits are not immediate). Furthermore, although solving climate change benefits everyone, its costs accrue to whoever is reducing emissions, which creates a logical structure in which the costs are for those who are born today, but the major benefits mostly happen far in the future. In other words, it comes down to asking this generation to invest for future generations, which generally is not something everyone agrees with. An inherent issue with climate change is that humans have a substantially short “weather memory”, and we generally consider the past 2-8 years as the normal climate condition (ref 14). Moreover, although climate change is happening globally, the costs hit different parts of the world disproportionately, and the local impacts can be completely different (e.g. climate change has increased coastal flooding in many regions, but it has also increased the growing season duration in northern latitudes), leading to non-cooperative conflicts. Therefore, it unfortunately seems unlikely that climate change is going to be perceived as an “acute crisis/catastrophe" that demands immediate global action, which makes climate change a complex problem and not a top priority for many people. The interplay between economic development and climate change is also a major challenge, where most people prefer having a full bank account today rather than spending on climate change mitigation (in order to avoid paying $$ later on in response to climate extremes in a warmer world). Thus, in the fight against climate change, it is essential to consider approaches that provide economic development while protecting the environment.

5. How can we tackle climate change?

Considering the grand challenge of climate change and its complexities, it is evident that tackling climate change requires significant efforts, and there is no exclusive solution for such. In general, the approaches for tackling climate change are classified into two primary categories:

• Adaptation: adjusting to life in a warmer world
• Mitigation: reducing climate change and heat trapping GHGs

5.1. Climate change adaptation:

Adaptation refers to efforts in response to climate change. In other words, we already know that the earth’s climate has warmed more than 1°C and the infrastructures designed decades ago are no longer effective for avoiding damages. For instance, flood events have intensified in some parts of the world, and one adaptation approach is to improve (or rebuild) physical flood protection measures such as dikes and levees. Another example is wildfire activities that have been substantially exacerbated in the past decade in areas such as California or Colorado, and global warming has a direct impact on it. Adaptive measures for wildfires may consist of using fire-resistant building materials, implementing prescribed controlled fires to reduce fuels across the larger areas, and employing more efficient fire monitoring, response and outreach efforts. The need for adaptation varies from place to place, depending on the sensitivity and vulnerability to environmental impacts. 

Adaptation efforts are generally costly and time dependent. For instance, after the Hurricane Katrina hit New Orleans in 2005 inundating 80% of the city and killing over 1600 people, the US Army Corps of Engineers came up with a multi-billion dollar plan to construct the “great wall of New Orleans” and protect the city from such disasters in the future (ref 15). Now the question in these cases is how much should be spent now (i.e. tall should the wall be) to avoid how much damage in the future (and for what duration)? For instance, one option is to spend $200 billion dollars to build a giant wall that will be over 40ft tall and probably no flood water can pass through it (an option that is most likely not economically reasonable), whereas another option is to spend $20 billion dollars now and $30 billion dollars more in 20 years and have gradual adaptation. With the ongoing global warming, the physical protective measures will more rapidly require upgrade (compared to the past), and thus solely relying on climate change adaptation does not seem economically sound and feasible.

5.2. Climate change mitigation:

The goal of climate change mitigation is to avoid significant human interference with the climate system, and stabilize greenhouse gas levels in a sufficient time frame. Thus, mitigation generally refers to the efforts for reducing or preventing emission of greenhouse gases (GHGs). The reason to avoid emissions is not to reverse climate change but to avoid additional warming and the associated climate damage.

Climate change mitigation is primarily carried out in two categories:

a. Reducing carbon emissions: which can be done by decarbonizing the electricity system (i.e. using renewable energy sources such as wind and solar or using nuclear energy) and shifting to non-gasoline transportation systems. 

b. Extracting carbon from the atmosphere (aka carbon sequestration): which refers to the extracting CO2 from the atmosphere and reducing its concentration. Carbon sequestration can be done either indirectly (by planting trees and vegetation) or direct air capture (using chemical processes to extract CO2 from air).

Over the past decade, there has been substantial advances in improving the efficiency and accessibility of renewable energies (especially solar energy), which partly stems from the government subsidies and resources. However, in many cases, we need energy when there is no sunshine or wind, and the energy storage systems are still not large enough for such a demand (notwithstanding the tremendous advances in storage systems in the past decade or so). On the other hand, nuclear energy is still a very high risk choice for many places (e.g. the 2011 Fukushima nuclear disaster that happened in Japan) and still not a sustainable option particularly due to the nuclear waste issue. Nonetheless, the research and development on nuclear energy is an ongoing topic, and a major global project (led by the European Union, USA, Russia, and Japan) is working on nuclear fusion power (ref 16), and deep isolation efforts (i.e. storing nuclear waste deep under the ground) have also come up with ways for storing nuclear waste (ref 17).

The carbon capture industry is also blooming and is expected to innovate in the coming decades, since some types of emissions are unlikely to be replaced in the near future (e.g. electric planes are still not feasible for long destinations). However, direct carbon capture is still quite expensive (over $100 per ton of CO2), and indirect carbon capture through reforestation is not scalable and it can revert all the captured carbon back to the atmosphere in case of a wildfire.

6. Summary

Human (anthropogenic) activities are the main cause of climate change which will have irreversible impacts in the future. Overall, tackling climate change requires multiple concurrent adaptation and mitigation efforts. The adaptive capacity should be increased to reduce the vulnerability of societies to climate stresses in order to reduce costs and damages of extreme events, decarbonizing efforts should be undertaken to reduce (and possibly net-zero) current emissions, and carbon sequestration tactics can accelerate the removal of CO2 from the atmosphere. In other words, climate adaptation efforts will have short- to medium-term effects, and climate mitigation approaches will target longer-term goals. An aggregate of breakthroughs (i.e. accumulation of a lot of tiny little improvements in various sectors) is essential for acting against climate change, and a global consensus is imperative for achieving such a goal.

References:

1. https://earthobservatory.nasa.gov/features/CarbonCycle
2. https://www.climate.gov/news-features/understanding-climate/climate-change-atmospheric-carbon-dioxide#:~:text=The%20global%20average%20atmospheric%20carbon,least%20the%20past%20800%2C000%20years.
3. https://www.edf.org/climate/climate-change-and-extreme-weather
4. https://svs.gsfc.nasa.gov/4853
5. https://www.aviso.altimetry.fr/en/data/products/ocean-indicators-products/mean-sea-level.html
6. https://www.nytimes.com/interactive/2020/09/24/climate/fires-worst-year-california-oregon-washington.html
7. https://www.pnas.org/content/113/42/11770.short
8. https://www.carbonbrief.org/qa-are-the-2019-20-locust-swarms-linked-to-climate-change
9. https://oceanservice.noaa.gov/facts/coralreef-climate.html
10. https://www.carbonbrief.org/mapped-how-climate-change-disproportionately-affects-womens-health
11. https://www.nature.com/articles/nclimate2470
12. https://www.sciencemag.org/news/2019/12/even-50-year-old-climate-models-correctly-predicted-global-warming
13. https://climate.nasa.gov/news/2943/study-confirms-climate-models-are-getting-future-warming-projections-right/
14. https://www.pnas.org/content/116/11/4905
15. https://www.takepart.com/feature/2015/08/17/katrina-new-orleans-walled-city
16. https://www.world-nuclear.org/information-library/current-and-future-generation/nuclear-fusion-power.aspx
17. https://www.deepisolation.com/press/deep-isolation-closes-20-million-series-a-raise-with-nac-international/