Sustainability in marketing refers to the integration of environmentally and socially responsible practices into the marketing strategies of businesses. The role of sustainability in marketing has become increasingly significant as consumers are more aware of environmental issues and demand more responsible corporate behavior. 

Here are several key aspects of this role:
1. Consumer Expectations
Today's consumers are more informed and concerned about sustainability. According to a Nielsen report, 66% of global consumers are willing to pay more for sustainable brands. This expectation drives companies to adopt sustainable practices as part of their marketing strategies to meet consumer demands.

2. Brand Differentiation
In a crowded market, sustainability can serve as a unique selling proposition (USP). Brands that effectively communicate their commitment to sustainability can differentiate themselves from competitors. For instance, Patagonia has built its brand around environmental activism, promoting its products as not only high-quality but also beneficial to the planet.

3. Corporate Social Responsibility (CSR)
Integrating sustainability into marketing is often part of a broader CSR strategy. Companies like Unilever have made sustainability a core aspect of their business model, focusing on reducing their environmental footprint and improving social impact. Their Sustainable Living brands, like Dove and Ben & Jerry's, have seen faster growth compared to other brands in their portfolio.

4. Transparency and Authenticity
Consumers today value transparency. Brands that openly share their sustainability efforts and the challenges they face in achieving their goals tend to build trust. For example, Allbirds emphasizes its use of natural materials and transparent carbon footprint information, fostering a sense of authenticity that resonates with eco-conscious consumers.

5. Innovation and Product Development
Sustainability drives innovation in product development. Companies are increasingly investing in sustainable materials and processes. The automotive industry is a prime example, with companies like Tesla leading the charge in electric vehicles (EVs) that promote sustainability while offering high performance, changing consumer perceptions of eco-friendly products.

6. Long-term Cost Savings
Emphasizing sustainability can also lead to long-term cost savings. Companies that implement sustainable practices often find efficiencies that reduce waste and lower operational costs. For instance, Walmart has committed to sustainability initiatives that include reducing emissions in its supply chain and increasing energy efficiency, resulting in significant cost savings.

7. Community Engagement
Brands that engage with their communities on sustainability initiatives can enhance their reputation and foster loyalty. For example, Ben & Jerry's actively participates in social justice campaigns and environmental initiatives, creating a community of loyal customers who share their values.

Conclusion
The role of sustainability in marketing is multifaceted, impacting consumer expectations, brand differentiation, corporate responsibility, transparency, innovation, cost savings, and community engagement. As businesses continue to recognize the importance of sustainable practices, those that effectively integrate sustainability into their marketing strategies will likely succeed in building strong, lasting relationships with consumers.

For further reading, consider exploring:
Harvard Business Review: The Sustainability Imperative
Forbes: The Importance of Sustainability in Marketing