There’s some recently published research on climate change1 that you can easily incorporate into your next lesson on metric conversions and unit analysis. The article gives a report on ocean heat content (OHC) measurements. Because 90% of the energy in our climate system is stored in the oceans, OHC measurements provide a strong indicator of global warming. In the report, the authors note that climate change and global warming are caused when:
“Human activities release greenhouse gases (GHGs) into the atmosphere, increasing their concentration and trapping heat within the climate system, which drives global heating.”1
In particular, the report focuses on changes in energy in our oceans. To this end, the authors state that:
“Global ocean heat content changes... show that there has been an unequivocal ocean warming trend in recent decades…Since 2007, the upper 2000 m ocean warming rate has been 11.1 zettajoules per year.”1
You can also see in the report that between 1958 and the end of 2024, the oceans have taken in about 420 ZJ of energy.1
Note that the authors use the metric prefix “zetta”, which refers to multiplication by 10 to the power of 21. Students can be challenged to write 11.1 ZJ or 420 ZJ in the numerical form with the appropriate amount of zeros: 11,100,000,000,000,000,000,000 and 420,000,000,000,000,000,000,000, respectively.
These amounts of energy are so ridiculously large that it’s hard to gain an understanding of the meaning of these measurements.
Some context can be provided by informing students that one of the atomic bombs detonated at the end of World War II released 63 TJ, or 63 terajoules, or energy.2 The prefix "tera" refers to multiplication by 10 to the power of 12, so 63 terajoules is 63,000,000,000,000 joules. Once this is determined, students can calculate the number of atomic bomb detonations it would take to release the same amount of energy in 11.1 ZJ or 420 ZJ (this works out to 11.1 ZJ = 176 million bombs and 420 ZJ = 6.7 billion bombs, respectively). If desired, students can be challenged to convert the current rate of warming (11.1 ZJ per year) to units of atomic bombs per second (this works out to 5.6 atomic bombs per second).
Further context can be added by noting that hurricanes can release up to 10,000 atomic bombs worth of energy.3 In this context, 11.1 ZJ and 420 ZJ compare to the energy released by 18,000 and 670,000 large hurricanes, respectively.
References:
- Cheng, L.; Abraham, J.; Trenberth, K.E. et al. Record High Temperatures in the Ocean in 2024. Adv. Atmos. Sci. 2025. https://doi.org/10.1007/s00376-025-4541-3(link is external)
- Pearson, E. F. Hurricane Ike versus an Atomic Bomb. J. Chem. Educ. 2013, 90, 90-92.
- Graham, S.; Riebeek, H. Hurricanes: The Greatest Storms on Earth. 2006. https://earthobservatory.nasa.gov/features/Hurricanes(link is external) (accessed January, 2005).
NGSS
Mathematical and computational thinking at the 9–12 level builds on K–8 and progresses to using algebraic thinking and analysis, a range of linear and nonlinear functions including trigonometric functions, exponentials and logarithms, and computational tools for statistical analysis to analyze, represent, and model data. Simple computational simulations are created and used based on mathematical models of basic assumptions. Use mathematical representations of phenomena to support claims.
Mathematical and computational thinking at the 9–12 level builds on K–8 and progresses to using algebraic thinking and analysis, a range of linear and nonlinear functions including trigonometric functions, exponentials and logarithms, and computational tools for statistical analysis to analyze, represent, and model data. Simple computational simulations are created and used based on mathematical models of basic assumptions. Use mathematical representations of phenomena to support claims.
Students who demonstrate understanding can analyze geoscience data to make the claim that one change to Earth’s surface can create feedbacks that cause changes to other Earth systems.
More information about all DCI for HS-ESS2 can be found https://www.nextgenscience.org/dci-arrangement/hs-ess2-earths-systems(link is external).
Analyze geoscience data to make the claim that one change to Earth's surface can create feedbacks that cause changes to other Earth systems.
Examples should include climate feedbacks, such as how an increase in greenhouse gases causes a rise in global temperatures that melts glacial ice, which reduces the amount of sunlight reflected from Earth’s surface, increasing surface temperatures and further reducing the amount of ice. Examples could also be taken from other system interactions, such as how the loss of ground vegetation causes an increase in water runoff and soil erosion; how dammed rivers increase groundwater recharge, decrease sediment transport, and increase coastal erosion; or how the loss of wetlands causes a decrease in local humidity that further reduces the wetland extent.
Students who demonstrate understanding can create a computational model to calculate the change in the energy of one component in a system when the change in energy of the other component(s) and energy flows in and out of the system are known.
*More information about all DCI for HS-PS3 can be found at https://www.nextgenscience.org/topic-arrangement/hsenergy(link is external).
Students who demonstrate understanding can create a computational model to calculate the change in the energy of one component in a system when the change in energy of the other component(s) and energy flows in and out of the system are known.
Assessment is limited to basic algebraic expressions or computations; to systems of two or three components; and to thermal energy, kinetic energy, and/or the energies in gravitational, magnetic, or electric fields.
Emphasis is on explaining the meaning of mathematical expressions used in the model.
Analyze a Major Global Challenge is a performance expectation related to Engineering Design HS-ETS1.
Analyze a major global challenge to specify qualitative and quantitative criteria and constraints for solutions that account for societal needs and wants.
Students analyze a major global problem. In their analysis, students: Describe the challenge with a rationale for why it is a major global challenge; Describe, qualitatively and quantitatively, the extent and depth of the problem and its major consequences to society and/or the natural world on both global and local scales if it remains unsolved; and Document background research on the problem from two or more sources, including research journals. Defining the process or system boundaries, and the components of the process or system: In their analysis, students identify the physical system in which the problem is embedded, including the major elements and relationships in the system and boundaries so as to clarify what is and is not part of the problem: and In their analysis, students describe* societal needs and wants that are relative to the problem. Defining the criteria and constraints: Students specify qualitative and quantitative criteria and constraints for acceptable solutions to the problem.