**1. Introduction**

Aviation is probably the most reliable means of disaster response and relief for most large-scale natural disasters. For example, it is unrealistic to maintain or repair road or rail connections across areas affected by earthquakes, floods, landslides, storms, or wildfires, to transport relief and aid to those affected. Thus, adaptation and risk management must pay particular attention to the strengthening of aviation infrastructure to guarantee robust and sustainable relief. By providing a perspective on the impacts on aviation of anticipated changed atmospheric conditions over the near future, this research addresses the adaptation of aviation transport to climate change. The greatest concerns of the aviation industry under a warming climate possibly are the following two questions: how will the maximum payload be affected by the warmer and lighter lower layer atmosphere? and, during the journey, will the changed ambient air properties (density, temperature and viscosity) affect the engine performance? Anyway, all current aviation engines are breathing

thermal engines. The first part of this chapter focuses on the maximum payload, whereas the second part concentrates on the effects on the efficiency and fuel consumption of the thermal engines. Commercial airliners provide an environmentfriendly express means of cargo transport and personnel travel (Section 7.4.1.2 of IPCC AR5 [1]). Possible effects of aviation on atmospheric components and climate already have been studied in detail [2–7]. Conversely, the the effects of climate warming on aviation have not yet been extensively studied. In Section 1 of this chapter, climate warming effects on aviation payload are investigated, based on the fact that air density is proportional to the maximum take-off weight (MTOW) for an aircraft, irrespective of the design (fixed wing or helicopters; jets or propellers). Aircraft are air-lifted and the MTOW can be expressed in a generic form as

$$\text{MTOW} = \text{M}\rho\_{\text{cl}} \left| \overrightarrow{\mathbf{V}\_{\text{0}}} \right|^{2}, \tag{1}$$

the ascending stage). So, a complete consideration of the issue involves the along flight route integration plus the potential energy changes of the entire aircraft. Discussion bifurcates in the following sections, focusing, respectively, on the effects on maximum payload (Section 2) and fuel efficiency (Section 3). This study should inspire further investigation into how climate and environmental changes

**2. Adverse effects on maximum payload from a warmer climate**

Air density is derivable from air pressure, temperature, and humidity [9, 10]:

where *P* is air pressure (*Pa*), *Rd* is dry air gas constant (�287 J/kg/K),*T* is absolute air temperature (K), and *q* is specific humidity (g/g). To apply Eq. (2) to near-surface level, atmospheric fields of pressure (*Ps*), temperature (*Ts*), and specific humidity *qs* at ground level (subscript "*s*" means surface) are required. These parameters fortunately are primary outputs from the coupled model intercomparison project (CMIP, e.g., https://cmip.ucar.edu/; Ref. [11]). The monthly climate model outputs are obtained from the IPCC Deutsches

*ρ<sup>a</sup>* ¼ *P=*½ � *RdT*ð Þ 1 þ 0*:*608*q* (2)

influence the civil aviation sector of industry.

*Twenty-seven GCM models used in this study.*

*Climate Warming and Effects on Aviation DOI: http://dx.doi.org/10.5772/intechopen.86871*

**2.1 Methods and data**

**Table 1.**

**177**

where *M* is airplane mechanical properties such as wing span area, attack

angle, and fuselage-wing interaction, *ρ<sup>a</sup>* is air density, and *V***<sup>0</sup>** ! is aircraft takingoff speed (for helicopters and other rotorcrafts, the angular speed of the rotor blades). If taking-off speed also is deemed as aircraft property, then air density is the sole environmental factor that is directly proportional to *MTOW*. In this study, near-surface (airport elevation) air density variations are examined over the twentieth and twenty-first centuries. For period with reanalysis data (1950–present), the loyalty of air density simulated by 27 climate models (**Table 1**) to reality also is examined. Based on the analyses, the decrease of maximum payload is examined, and the inter-model spread of the uncertainty assessed up to 2100. The largest uncertainty in the degree of warming resides with the industrial emission of GHGs and other pollutants in the atmosphere to which climate is sensitive to the extra radiative forcing, because modern climate has a clear footprint of human activity [2, 8]. The future state of climate would depend crucially on what emission controls nations chose to impose. Emission scenarios (ESs) describe future release into the atmosphere of GHGs, aerosols, and other pollutants. ESs and other boundary conditions are inputs to climate models. In the most recent Intergovernmental Panel on Climate Change (IPCC) assessment report (AR5), the driving scenario is in the form of representative concentration pathways (RCPs). In this study, the climate model outputs under high scenario RCP 8.5 (meaning that rising radiative forcing pathway leads to 8.5 W/m<sup>2</sup> heating effects in 2100) are used.

The second theme of this chapter is on aviation fuel efficiency. According to FAA regulations, the flight profile consists the seven stages (A-G from taxi out till taxi in). To estimate the extra work that needs to be performed, along flight route integration is the exact approach. Because the commercial data on flight logs are not available for us, we have to make some assumptions according to the carrier aircraft and the routes, which are readily available online (e.g., from those websites selling air tickets). Unlike the issue with maximum payload, where only the airport level air density plays the decisive role, temperature, air density, and winds all matter in the fuel efficiency issue. There sure exist apparent canceling effects among them as well. In addition, the tropopause's elevation will fluctuate as climate warms; this involves extra potential energy cost in case the aircraft still cruise in the coldest (hence the most favorable for the thermal engine) and most clear level of the Earth's atmosphere. This likely is the case since the cruise stage is the most fuel-consuming stage of the flight (although the rate of fuel burning is only a half of

## *Climate Warming and Effects on Aviation DOI: http://dx.doi.org/10.5772/intechopen.86871*

thermal engines. The first part of this chapter focuses on the maximum payload, whereas the second part concentrates on the effects on the efficiency and fuel consumption of the thermal engines. Commercial airliners provide an environmentfriendly express means of cargo transport and personnel travel (Section 7.4.1.2 of IPCC AR5 [1]). Possible effects of aviation on atmospheric components and climate already have been studied in detail [2–7]. Conversely, the the effects of climate warming on aviation have not yet been extensively studied. In Section 1 of this chapter, climate warming effects on aviation payload are investigated, based on the fact that air density is proportional to the maximum take-off weight (MTOW) for an aircraft, irrespective of the design (fixed wing or helicopters; jets or propellers).

*Environmental Impact of Aviation and Sustainable Solutions*

Aircraft are air-lifted and the MTOW can be expressed in a generic form as

angle, and fuselage-wing interaction, *ρ<sup>a</sup>* is air density, and *V***<sup>0</sup>**

effects in 2100) are used.

**176**

*MTOW* ¼ M*ρ<sup>a</sup> V***<sup>0</sup>**

where *M* is airplane mechanical properties such as wing span area, attack

off speed (for helicopters and other rotorcrafts, the angular speed of the rotor blades). If taking-off speed also is deemed as aircraft property, then air density is the sole environmental factor that is directly proportional to *MTOW*. In this study, near-surface (airport elevation) air density variations are examined over the twentieth and twenty-first centuries. For period with reanalysis data (1950–present), the loyalty of air density simulated by 27 climate models (**Table 1**) to reality also is examined. Based on the analyses, the decrease of maximum payload is examined, and the inter-model spread of the uncertainty assessed up to 2100. The largest uncertainty in the degree of warming resides with the industrial emission of GHGs and other pollutants in the atmosphere to which climate is sensitive to the extra radiative forcing, because modern climate has a clear footprint of human activity [2, 8]. The future state of climate would depend crucially on what emission controls nations chose to impose. Emission scenarios (ESs) describe future release into the atmosphere of GHGs, aerosols, and other pollutants. ESs and other boundary conditions are inputs to climate models. In the most recent Intergovernmental Panel on Climate Change (IPCC) assessment report (AR5), the driving scenario is in the form of representative concentration pathways (RCPs). In this study, the climate model outputs under high scenario RCP 8.5 (meaning that rising radiative forcing pathway leads to 8.5 W/m<sup>2</sup> heating

The second theme of this chapter is on aviation fuel efficiency. According to FAA regulations, the flight profile consists the seven stages (A-G from taxi out till taxi in). To estimate the extra work that needs to be performed, along flight route integration is the exact approach. Because the commercial data on flight logs are not available for us, we have to make some assumptions according to the carrier aircraft and the routes, which are readily available online (e.g., from those websites selling air tickets). Unlike the issue with maximum payload, where only the airport level air density plays the decisive role, temperature, air density, and winds all matter in the fuel efficiency issue. There sure exist apparent canceling effects among them as well. In addition, the tropopause's elevation will fluctuate as climate warms; this involves extra potential energy cost in case the aircraft still cruise in the coldest (hence the most favorable for the thermal engine) and most clear level of the Earth's atmosphere. This likely is the case since the cruise stage is the most fuel-consuming stage of the flight (although the rate of fuel burning is only a half of

! 

 **2**

*,* (1)

is aircraft taking-

!


#### **Table 1.** *Twenty-seven GCM models used in this study.*

the ascending stage). So, a complete consideration of the issue involves the along flight route integration plus the potential energy changes of the entire aircraft. Discussion bifurcates in the following sections, focusing, respectively, on the effects on maximum payload (Section 2) and fuel efficiency (Section 3). This study should inspire further investigation into how climate and environmental changes influence the civil aviation sector of industry.
