Introduction:
Climate change has a disproportionate impact on women in comparison to men, and women have a key role to play in climate adaptation. However, evidence is lacking on how gender inequalities may be associated with climate vulnerability and ability to respond at country level.

Methods:
This ecological study investigated the association between climate adaptation, measured by the Notre Dame Global Adaptation Initiative Country Index (ND-GAIN), and gender equality, measured by the Global Gender Gap Index (GGGI) developed by the World Economic Forum and the Gender Inequality Index (GII) developed by the United Nations. Simple linear regression was used to estimate the associations between the indices and their subdomains for 146 countries.

Results:
There was an approximately linear association between the GGGI and climate adaptation. Each 1% increase in gender equality was associated with a 0.6% increase in the ND-GAIN score (the slope was 0.59, with a 95% confidence interval [0.33 to 0.84]). This was driven by a negative association between gender equality and vulnerability (-0.41 [-0.62 to -0.20]), and a positive association between gender equality and readiness (0.77 [0.44 to 1.10]). The strongest associations between gender equality and climate adaptation were observed for the education domain of the GGGI. There was a strong negative linear association between the GII and climate adaptation, which explained most (86%) of the between-country variation in climate adaptation. Each 1% increase in gender inequality was associated with a 0.5% decrease in the ND-GAIN score (-0.54 [-0.57 to -0.50]). The association between gender inequality and readiness was stronger than the association with vulnerability (0.41 [0.37 to 0.44] for vulnerability versus − 0.67 [-0.72 to -0.61] for readiness).

Conclusions:
Gender inequality, measured broadly across different domains of life, is associated with climate adaptation at country level, both in terms of vulnerability to impact and readiness to respond.